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Cited by 262Thermoregulation and physiological responsesThermal Regulation in MedicineCircadian rhythm and melatonin

Temperature regulation in women: Effects of the menstrual cycle

Open access
Baker, Fiona C., Siboza, Felicia, Fuller, Andrea·2020·Temperature
DOI 10.1080/23328940.2020.1735927PMC PMC7575238
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Abstract

Core body temperature changes across the ovulatory menstrual cycle, such that it is 0.3°C to 0.7°C higher in the post-ovulatory luteal phase when progesterone is high compared with the pre-ovulatory follicular phase. This temperature difference, which is most evident during sleep or immediately upon waking before any activity, is used by women as a retrospective indicator of an ovulatory cycle. Here, we review both historical and current literature aimed at characterizing changes in core body temperature across the menstrual cycle, considering the assessment of the circadian rhythm of core body temperature and thermoregulatory responses to challenges, including heat and cold exposure, exercise, and fever. We discuss potential mechanisms for the thermogenic effect of progesterone and the temperature-lowering effect of estrogen, and discuss effects on body temperature of exogenous formulations of these hormones as contained in oral contraceptives. We review new wearable temperature sensors aimed at tracking daily temperature changes of women across multiple menstrual cycles and highlight the need for future research on the validity and reliability of these devices. Despite the change in core body temperature across the menstrual cycle being so well identified, there remain gaps in our current understanding, particularly about the underlying mechanisms and microcircuitry involved in the temperature changes.

AI snapshot

Written from the paper’s full text.

TL;DR

This review synthesizes historical and current evidence that core body temperature is higher in the luteal phase than the follicular phase and that thermoregulatory thresholds shift upward with high progesterone. It also highlights unresolved mechanisms, limited data on fever across the cycle, and the need for independent validation of wearable temperature-tracking devices.

Key findings

  • Resting/basal core body temperature is 0.3°C to 0.7°C higher in the luteal phase than the follicular phase, and most 24-h studies show an increased mesor and a blunted nocturnal decline/amplitude in the luteal phase.
  • Controlled constant-routine and ultradian nap studies generally find no change in circadian phase of core body temperature between follicular and luteal phases, though some semi-controlled studies report phase delays.
  • Progesterone has a thermogenic effect, estrogen has a temperature-lowering effect, and the progesterone:estrogen ratio—rather than progesterone alone—may be critical for the luteal-phase core body temperature increase and blunted amplitude.
  • Wearable devices show promise for tracking ovulatory cycles, but the review notes that independent validation against gold standards is still needed; one wrist-skin study detected a pre-ovulatory temperature nadir in only 41% of cycles.

Methods

  • Narrative literature review using PubMed and Google Scholar searches for English-language, peer-reviewed clinical and experimental studies on the menstrual cycle and body temperature.
  • Search terms included circadian rhythm, progesterone, estrogen/estradiol, luteal phase, follicular phase, ovulation, vasodilation, hypothalamus, oral contraceptives, exercise, heating, heat, fever, cooling, cold, and wearable sensors.
  • The review summarizes studies in tables, including 24-h core body temperature studies across menstrual cycle phases and commercial wearable/app studies.

Limitations

  • The authors state that mechanisms and microcircuitry underlying menstrual-cycle temperature changes remain incompletely understood, and that there are no data comparing fever patterns in women across menstrual cycle phases.
  • The authors state that further independent evaluation of wearable validity and reliability is required, and they note a broader paucity of data from females in biological research.
  • Evident from the text: this is a narrative review without a formal systematic-review or meta-analytic protocol; many included studies have small samples, varied measurement sites and protocols, and some rely on self-reported menstrual phase rather than confirmed ovulation.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1080/23328940.2020.1735927

Cites

188 of 188 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 342 cited sources checked · 0 supported · 0 flagged

  • Findingcitation
    § Methods

    There is not always a correlation between the progesterone rise and the core body temperature rise.

    “There is not always a correlation between the progesterone rise and the core body temperature rise.”
    Quote in the paperNot a substantial claim
  • Premisecitation
    § Methods

    Vaginal temperature provides very similar values to rectal temperature.

    “Vaginal temperature provides very similar values to rectal temperature [34].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [34] source

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  • Premisenone given
    § ABSTRACT

    The temperature difference is most evident during sleep or immediately upon waking before any activity.

    “This temperature difference, which is most evident during sleep or immediately upon waking before any activity, is used by women as a retrospective indicator of an ovulatory cycle.”
    Quote in the paperNot a substantial claim
  • Premisecitation
    § Methods

    Central arterial or mixed venous blood temperature best represents the general thermal status of the body.

    “The general thermal status of the body is best represented by central arterial or mixed venous blood temperature [27], which is technically difficult to measure.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [27] Brengelmann GL, 1987

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  • Premisecitation
    § Methods

    Esophageal temperature is considered the best approximate of blood temperature.

    “Of those, esophageal is considered the best approximate of blood temperature [28], and it has been used in some of the key early studies demonstrating changes in body temperature regulation across the menstrual cycle [for example, 29-31].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [28] Mitchell D, 1985, Physiologist

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    Findingnone given
    § Methods

    As far as the authors are aware, there are no data comparing patterns of fevers in women across phases of the menstrual cycle.

    “As far as we are aware, there are no data comparing patterns of fevers in women across phases of the menstrual cycle.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given
    § Methods

    The 24-h rhythm in core body temperature is influenced by sleep, activity, and meals.

    “When not living under constant conditions, the 24-h rhythm in core body temperature is still apparent, however, in addition to circadian influences, it is influenced by other factors, including sleep, which lowers nocturnal core body temperature further, and activity and meals, which raise core body temperature.”
    Quote in the paperNot a substantial claim

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    Premisecitation
    § Methods

    The amplitude of the circadian rhythm of core body temperature can change as a result of season, photoperiod, energy intake, water balance, disease, and reproductive status.

    “In addition to these factors, the amplitude of the circadian rhythm of core body temperature can change as a result of the season, photoperiod, energy intake, water balance, disease, and reproductive status [23].”
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    Premisecitation
    § Methods

    Both heat production and heat loss contribute to the circadian variation in heat content, leading to a circadian rhythm in core body temperature.

    “Both heat production and heat loss contribute to the circadian variation in heat content, leading to a circadian rhythm in core body temperature [22].”
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    • cites [22] source

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    Premisecitation
    § Methods

    Core body temperature has an endogenously generated circadian rhythm with a period close to 24-h, which is evident even when environmental conditions are kept constant.

    “Core body temperature has an endogenously generated circadian rhythm with a period close to 24-h, which is evident even when environmental conditions are kept constant, free of influences from sleep-wake patterns, activity, meals, or light exposure [18,19].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [18] Keefe DL, 1985, Oxford RevReprod Biol

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    • cites [19] source

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Introduction

    A biphasic rhythm in basal core body temperature across the menstrual cycle, with body temperature higher in the luteal phase after ovulation, was described more than 100 years ago by Squire in 1868 and van de Velde in 1928.

    “A biphasic rhythm in basal core body temperature across the menstrual cycle, with body temperature higher in the luteal phase after ovulation, was described more than 100 years ago by Squire in 1868 and van de Velde in 1928 [cited in 1].”
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    Premisecitation
    § Methods

    Rectal temperature is the next best measure of core body temperature after esophageal, but is slow to respond to changes in the thermal status of the body.

    “Rectal temperature, with the probe carefully inserted to the correct depth [26], is the next best measure, with the drawback being that it is slow to respond to changes in the thermal status of the body [for example, see 29].”
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    Premisecitation
    § Methods

    The thermoregulatory network consists of a central integrative circuit in the preoptic area of the hypothalamus (POA), which orchestrates the activation of thermoeffector mechanisms in response to input from peripheral and central thermoreceptors.

    “The thermoregulatory network consists of a central integrative circuit in the preoptic area of the hypothalamus (POA), which orchestrates the activation of thermoeffector mechanisms in response to input from peripheral and central thermoreceptors [4].”
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    • cites [4] source

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    Premisecitation
    § Methods

    Detection of changes in the circadian rhythm of core body temperature across the menstrual cycle requires continuous data recording, which can be achieved accurately and relatively noninvasively through ingestible telemetry pills.

    “Detection of changes in the circadian rhythm of core body temperature across the menstrual cycle requires continuous data recording, which can be achieved accurately and relatively noninvasively through the use of ingestible telemetry pills [35].”
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    • cites [35] source

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    Premisenone given
    § ABSTRACT

    Women use the temperature difference as a retrospective indicator of an ovulatory cycle.

    “This temperature difference, which is most evident during sleep or immediately upon waking before any activity, is used by women as a retrospective indicator of an ovulatory cycle.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Thermoregulation involves a balance between heat gain and heat loss such that a constant core body temperature can be maintained.

    “Thermoregulation involves a balance between heat gain (metabolic heat production and dry heat gain from the environment) and heat loss (dry and evaporative heat loss to the environment) such that a constant core body temperature can be maintained [8].”
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    • cites [8] source

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    Premisecitation
    § Methods

    Gastrointestinal temperature is similar to rectal temperature (on average about 0.1°C higher), but changes as the sensor moves along the gastrointestinal tract and is influenced by drinking liquids.

    “The temperature of the gastrointestinal tract is also similar to that of the rectum (on average, about 0.1°C higher), but it does change as the sensor (typically an ingested telemetry pill) moves along the gastrointestinal tract, and is influenced by drinking liquids [26].”
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    Premisecitation
    § Methods

    In most placental mammals, core body temperature is regulated around 37°C.

    “In most placental mammals, core body temperature is regulated around 37°C [9,10].”
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    • cites [9] source

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    Premisenone given
    § Methods

    The core body temperature curve recorded under constant conditions is one of the gold standard methods to quantify or demonstrate circadian phase.

    “The core body temperature curve recorded under constant conditions is one of the gold standard methods to quantify or demonstrate circadian phase, or the output of the central clock (along with melatonin).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Methods

    Core body temperature oscillates between a maximum in the active period and a minimum during the inactive period, with an amplitude of 0.8°C to 1.0°C.

    “Core body temperature continues to oscillate independently of other physiological rhythms or external time cues between a maximum in the active period (daytime for humans) and a minimum during the inactive period (nocturnal for humans), with an amplitude of 0.8°C to 1.0°C [21].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] Moore-Ede MC, 1982

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    Premisecitation
    § Methods

    Progesterone rises early in the luteal phase, inhibits pulsatile GnRH and LH release, and prevents the positive feedback effect of elevated estrogen on GnRH and LH.

    “Progesterone, on the other hand, which rises early in the luteal phase, inhibits pulsatile GnRH and, consequently, LH release; it also prevents the positive feedback effect of elevated estrogen on GnRH and LH [44].”
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    • cites [44] source

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    Premisecitation
    § Methods

    The circadian rhythm of distal skin temperature is phase-advanced by approximately 100 min and has a larger amplitude than that of core body temperature.

    “As described above, studies that have investigated skin and core body temperature under constant routine conditions when ambient temperature and behavior are controlled, have shown that the circadian rhythm of distal skin (hands and feet) temperature is phase-advanced, by approximately 100 min, and with a larger amplitude than that of core body temperature [10].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10] source

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    Premisecitation
    § Methods

    Assays used to measure endogenous progesterone and estrogen do not measure synthetic hormones, and there is a large variation between individuals in the pharmacokinetics of contraceptive steroids.

    “It should be noted that the assays used to measure endogenous progesterone and estrogen (typically estradiol) do not measure synthetic hormones and there is a large variation between individuals in the pharmacokinetics of contraceptive steroids [53].”
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    • cites [53] source

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    Premisecitation
    § Methods

    In over 120,000 women using the Natural Cycle app, mean cycle length was 29.3 days, mean follicular phase length was 16.9 days (95%CI: 10 to 30 days), and mean luteal phase length was 12.4 days (95%CI: 7 to 17 days).

    “Consistent with established clinical research, prospective data collected from multiple menstrual cycles in over 120,000 women (~612,000 cycles) using the Natural Cycle app, which included daily basal oral temperature measurement, dates of menstruation, and results of an ovulation prediction kit for some cycles, revealed a mean cycle length of 29.3 days, with a mean follicular phase length of 16.9”
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    • cites [39] source

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    Premisecitation
    § Methods

    The mean LH peak occurs at 14.7 ± 2.4 days.

    “The mean LH peak occurs at 14.7 ± 2.4 days [38].”
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    Premisecitation
    § Methods

    Kisspeptin and neurokinin B play a key role in regulating GnRH and subsequent gonadotropin secretion.

    “Kisspeptin and neurokinin B, neuropeptides secreted by the ventral hypothalamus, play a key role in regulating GnRH and subsequent gonadotropin secretion [45].”
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    Interpretationcitation
    § Methods

    The POA of the hypothalamus is centrally important for the regulation of both temperature and reproductive function, and there is a linkage between these two systems.

    “The POA of the hypothalamus is centrally important for the regulation of both temperature and reproductive function, and there is a linkage between these two systems.”
    Quote in the paperNot a substantial claim

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    Premisecitation
    § Methods

    The follicular phase has an interval of between 10 and 20 days and the luteal phase of between 9 and 17 days, with greater inter-individual variance for the follicular phase.

    “The follicular phase has an interval of between 10 and 20 days and the luteal phase of between 9 and 17 days, with greater inter-individual variance for the follicular phase [38].”
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    Premisenone given
    § Methods

    Combined oral contraceptives typically contain ethinyl estradiol and a synthetic progestin taken for 21 days, and a placebo taken for 7 days.

    “Combined oral contraceptives typically contain ethinyl estradiol and a synthetic progestin taken for 21 days, and a placebo taken for 7 days.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given
    § Methods

    The length of the menstrual cycle, timing of ovulation, and hormonal concentrations at any particular timepoint in the menstrual cycle vary between individuals and even from month to month within an individual.

    “The length of the menstrual cycle, timing of ovulation, and hormonal concentrations at any particular timepoint in the menstrual cycle vary between individuals and even from month to month within an individual.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given
    § Methods

    About 7 days after ovulation, if fertilization and implantation of the conceptus do not occur, the corpus luteum degenerates and hormone production begins to decline.

    “About 7 days after ovulation, should fertilization and implantation of the conceptus not occur, the corpus luteum degenerates and hormone production begins to decline.”
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    Premisecitation
    § Methods

    Detection of LH in urine using an over-the-counter device is considered a highly accurate marker of impending ovulation.

    “Detection of LH in urine using an over-the-counter device is considered a highly accurate marker of impending ovulation [43].”
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    Premisecitation
    § Methods

    Second-generation progestins are more androgenic, and third-generation progestins are anti-androgenic.

    “The type of progestin has also varied with generations of oral contraceptive: second-generation progestins (e.g. norgesterel) are more androgenic, and third-generation progestins are anti-androgenic [52].”
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    Premisenone given
    § Methods

    Oral contraceptive brands differ in the hormonal dose delivered across the 21-day period, with monophasic pills containing a constant dose of progestin and estrogen, and triphasic pills containing a varying dose of hormones designed to mimic the natural menstrual cycle.

    “Finally, oral contraceptive brands differ in the hormonal dose delivered across the 21-day period, with monophasic pills containing a constant dose of progestin and estrogen, and triphasic pills containing a varying dose of hormones designed to mimic the natural menstrual cycle.”
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    Premisereasoning
    § Methods

    Most studies describing core body temperature changes in detail across the menstrual cycle have focused on pre-menopausal women with regular menstrual cycles, and there are very little data in peri-menopausal women.

    “Given these constraints, most studies describing core body temperature changes in detail across the menstrual cycle have focused on pre-menopausal women with regular menstrual cycles, and there are very little data in peri-menopausal women.”
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    Premisecitation
    § Methods

    In the late follicular phase, when estradiol concentration has exceeded >200 pg.ml−1 for ~48 h, it switches to exerting positive feedback on the hypothalamic-pituitary system, sensitizing the pituitary to GnRH, leading to the mid-cycle LH surge.

    “In the late follicular phase, as ovarian follicles develop and mature, estradiol is secreted in large amounts; when the estradiol concentration has exceeded a certain threshold for a certain amount of time (>200 pg.ml−1 for ~48 h [43]), it switches to exerting positive feedback on the hypothalamic-pituitary system, sensitizing the pituitary to the hypothalamic peptide gonadotrophin-releasing”
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    Premisecitation
    § Methods

    Mean cycle length decreased significantly with age, by 3.2 days from age 25 to 45 years.

    “Mean cycle length decreased significantly with age, by 3.2 days from age 25 to 45 years.”
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    • cites [39] source

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    Premisecitation
    § Methods

    Hormonal contraceptives are exogenous steroid hormones that inhibit GnRH, thus suppressing the secretion of gonadotropins.

    “Hormonal contraceptives are exogenous steroid hormones that inhibit GnRH, thus suppressing the secretion of gonadotropins; during the placebo interval, the hypothalamic–pituitary–ovarian axis slowly regains activity, however, endogenous estrogen levels remain suppressed until Day 6 [50].”
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    Premisecitation
    § Methods

    Women taking oral contraceptives have low endogenous hormone levels but high levels of synthetic hormones.

    “Women taking oral contraceptives have low endogenous hormone levels but high levels of synthetic hormones [52].”
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    Premisenone given
    § Methods

    Approximately 16 h after the peak LH surge, an oocyte is released from the follicle (ovulation) and the corpus luteum then evolves from the ruptured follicle and secretes progesterone and estradiol, marking the start of the luteal phase.

    “Approximately 16 h after the peak LH surge, an oocyte is released from the follicle (ovulation) and the corpus luteum then evolves from the ruptured follicle and secretes progesterone and estradiol, marking the start of the luteal phase.”
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    Premisecitation
    § Methods

    Ethinyl estradiol has a high affinity for estrogen (estradiol) receptors and is more potent and may be bioactive for longer than the endogenous hormone.

    “For example, ethinyl estradiol has a high affinity for estrogen (estradiol) receptors and is more potent [52] and may be bioactive for longer [51] than the endogenous hormone.”
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    Premisecitation
    § Methods

    The reduction in ovarian steroid hormones toward the end of the luteal phase leads to reduced negative feedback on the hypothalamic-pituitary system, and there is an inter-cycle rise in FSH.

    “The reduction in ovarian steroid hormones (along with reduced inhibin A concentrations) toward the end of the luteal phase leads to a reduced negative feedback mechanism on the hypothalamic-pituitary system, and there is an inter-cycle rise in FSH [42].”
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    Premisecitation
    § Methods

    Estradiol is the main secretory product of the ovarian follicle during the early follicular phase and, together with inhibin, is primarily responsible for inducing negative feedback regulation on FSH and LH release from the pituitary.

    “Estradiol (the most potent estrogen) is the main secretory product of the ovarian follicle during the early follicular phase of the cycle and, together with inhibin, is primarily responsible for inducing a negative feedback regulation on the release of the gonadotrophins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), from the pituitary [41,42].”
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    Premisecitation
    § Methods

    The human menstrual cycle typically lasts 25 to 35 days, with an average of 28 days for women in their twenties, and 26 days for women in their forties.

    “The human menstrual cycle, defined as the interval between the first day of bleeding of one cycle and first day of bleeding of the next cycle, typically lasts 25 to 35 days, with an average of 28 days for women in their twenties, and 26 days for women in their forties [37].”
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    Premisecitation
    § Methods

    During the placebo interval of oral contraceptives, the hypothalamic-pituitary-ovarian axis slowly regains activity, but endogenous estrogen levels remain suppressed until Day 6.

    “Hormonal contraceptives are exogenous steroid hormones that inhibit GnRH, thus suppressing the secretion of gonadotropins; during the placebo interval, the hypothalamic–pituitary–ovarian axis slowly regains activity, however, endogenous estrogen levels remain suppressed until Day 6 [50].”
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    Premisecitation
    § Methods

    The impact of confounding factors on basal core body temperature can be somewhat lessened by following the "three-over-six" rule.

    “The impact of confounding factors can be somewhat lessened by following the “three-over-six” rule”
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    Premisecitation
    § Methods

    Melatonin increases during the night and has a hypothermic effect, contributing to the normal nocturnal decline in core body temperature.

    “Melatonin, which increases during the night, has a hypothermic effect, contributing to the normal nocturnal decline in core body temperature [77]”
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    Premisecitation
    § Methods

    Even when basal core body temperature is measured on awakening before activity, it is influenced by internal factors such as fever, sleep disturbance, and change of waking time, and external factors such as environmental temperature, which can confound measurement of a menstrual cycle effect.

    “Even if basal core body temperature is measured on awakening before any activity, it is still influenced by internal (e.g. fever, sleep disturbance, change of waking time) and external (e.g. environmental temperature) factors, which can confound the measurement of a menstrual cycle effect on body temperature [43]”
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    Interpretationnone given
    § Methods

    Core body temperature rhythms in women in the follicular phase are most similar to those of men.

    “Core body temperature rhythms in women in the follicular phase are most similar to those of men.”
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    Premisecitation
    § Methods

    The "three-over-six" rule requires that three consecutive daily readings are higher than the six preceding daily readings, reflecting an upward trend in core body temperature.

    “which requires that three consecutive daily readings are higher than the six preceding daily readings, reflecting an upward trend in core body temperature [1]”
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    Premisecitation
    § Methods

    Grant and colleagues found that both the area under the curve for progesterone and for the progesterone:estrogen ratio correlated with the core body temperature area under the curve.

    “Grant, and colleagues [76] found that both the area under the curve for progesterone and for the progesterone:estrogen ratio correlated with the core body temperature area under the curve”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [76] Grant LK, 2019, Sleep

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationcitation
    § Methods

    Progesterone may inhibit the nocturnal hypothermic action of melatonin in the luteal phase, reducing the nocturnal fall in core body temperature.

    “The authors reasoned that progesterone may inhibit the nocturnal hypothermic action of melatonin in the luteal phase, reducing the nocturnal fall in core body temperature [66]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [66] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning
    § Methods

    Core body temperature remains high until the approach to menstruation, when it declines as progesterone levels decline.

    “remaining high until the approach to menstruation, when it declines as progesterone levels decline”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation
    § Methods

    Administration of melatonin provokes an increase in distal skin temperature and a decrease in core body temperature, as heat is shifted from the core to the shell.

    “administration of melatonin provokes an increase in distal skin temperature (potentially via a direct effect on blood vessels to induce vasodilation and/or indirectly via modulation of sympathetic nervous system activity) and a decrease in core body temperature [10], as heat is shifted from the core to the shell.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [10] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Melatonin administered during the day elevated circulating melatonin levels to a similar extent in the follicular and luteal phases, and was associated with a decline in core body temperature in the follicular phase (of 0.31°C), but no associated decline in core body temperature in the luteal phase.

    “Melatonin administered during the day elevated circulating melatonin levels to a similar extent in the follicular and luteal phases, and was associated with a decline in core body temperature in the follicular phase (of 0.31°C), but no associated decline in core body temperature in the luteal phase [66]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [66] source

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  • May combine two claims.

    Premisecitation
    § Methods

    In a small study of four women in the preovulatory phase with documented high estradiol levels, resting esophageal temperature was lower and the threshold for sweating was decreased relative to the early follicular phase.

    “In a small study of four women in the preovulatory phase, in whom high levels of estradiol were documented, resting esophageal temperature was lower and the threshold for sweating was decreased relative to the early follicular phase [31].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [31] source

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Some investigators found a phase delay in the temperature rhythm, sometimes by as much as 90 min, in the luteal phase compared with the follicular phase.

    “Some investigators [66–68,80] found a phase delay in the temperature rhythm (sometimes by as much as 90 min) in the luteal phase compared with the follicular phase”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [66] source

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    • cites [67] source

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    • cites [68] source

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    • cites [80] source

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Other investigators found no difference in the phase of the temperature rhythm between the luteal and follicular phases.

    “while others have found no difference [35,69,71,79]”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [35] source

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    • cites [69] source

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    • cites [71] source

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    • cites [79] source

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  • May combine two claims.

    Premisecitation
    § Methods

    Shibui et al. found a blunted amplitude of thyroid-stimulating hormone and a trend for a lower area under the melatonin curve, in addition to a blunted temperature rhythm, in women in the follicular versus luteal phase.

    “Shibui and colleagues [73] investigated multiple circadian hormone and temperature rhythms in women in the follicular versus luteal phase and found a blunted amplitude of thyroid-stimulating hormone and a trend for a lower area under the melatonin curve, in addition to a blunted temperature rhythm”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [73] source

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  • Classified as probably not a substantial claim.

    Interpretationcitation
    § Methods

    Shechter et al. concluded that the changes in amplitude and level of core body temperature in the luteal phase likely reflect a thermoregulatory response to progesterone rather than a change in function of the circadian system.

    “Shechter et al. [83],concluded that the changes in amplitude and level of core body temperature in the luteal phase likely reflect a thermoregulatory response to progesterone rather than a change in function of the circadian system.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [83] source

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  • May combine two claims.

    Interpretationcitation
    § Methods

    The increase in spindle frequency activity in the luteal phase may be in part a result of increased core body temperature, although progesterone and its metabolites likely also have a direct effect on spindle generation.

    “The well-characterized increase in spindle frequency activity in the luteal phase [86–88] may also be, in part, a result of increased core body temperature [89], although progesterone and its metabolites likely also have a direct effect on spindle generation [84].”
    Quote in the paperNot a substantial claim0 of 5 sources checked
    • cites [86] source

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    • cites [87] source

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    • cites [88] Driver HS, 1996, J Clin Endocrinol Metab

      Not checked in the free run.

    • cites [89] source

      Not checked in the free run.

    • cites [84] source

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  • May combine two claims.

    Interpretationreasoning
    § Methods

    In the presence of estrogen and progesterone in the luteal phase, the core body temperature curve is shifted upwards but with a blunted amplitude.

    “whereas in the presence of estrogen and progesterone in the luteal phase, the curve is shifted upwards but with a blunted amplitude.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation
    § Methods

    Driver et al. suggested that the higher slow-wave activity may be attributed to the higher body temperature since slow-wave activity is increased with elevated body temperature in the rat.

    “which they suggest may be attributed to the higher body temperature since slow-wave activity is increased with elevated body temperature in the rat [85].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [84] source

      Not checked in the free run.

    • cites [85] Gao B, 1995, Am J Physiol

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning
    § Methods

    Overall, current evidence supports the concept that the amplitude of the circadian core body temperature rhythm is blunted in the luteal phase, but the circadian core body temperature phase is unchanged in the luteal phase compared with the follicular phase.

    “Overall, current evidence supports the concept that the amplitude of the circadian core body temperature rhythm is blunted in the luteal phase, but the circadian core body temperature phase is unchanged in the luteal phase compared with the follicular phase of the menstrual cycle.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation
    § Methods

    REM sleep has a circadian variation, peaking soon after the nadir in core body temperature, and may be inhibited in the presence of a higher core body temperature, as it is under a thermal challenge; thermoregulatory responses are reduced in REM sleep.

    “REM sleep has a circadian variation, peaking soon after the nadir in core body temperature [90], and may be inhibited in the presence of a higher core body temperature, as it is under a thermal challenge [91]; thermoregulatory responses (e.g. sweating rate) are reduced in REM sleep [92].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [90] source

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    • cites [91] source

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    • cites [92] Sagot JC, 1987, Am J Physiol

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  • Classified as probably not a substantial claim.

    Interpretationcitation
    § Methods

    Shibui et al. concluded that there is an overall change in the circadian pacemaker.

    “leading them to conclude that there is an overall change in the circadian pacemaker”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [73] source

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation
    § Methods

    Since the onset of sweating is delayed yet cutaneous vasodilation is increased during the luteal phase, the net result may be no change, or little change, in skin temperature.

    “These authors suggest that since the onset of sweating is delayed (which would be expected to be associated with an increase in skin temperature) yet cutaneous vasodilation is increased (increasing convective heat loss) during the luteal phase, the net result may be no change, or little change, in skin temperature [36].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [36] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Methods

    Shechter et al. found reduced REM sleep in naps during the habitual nocturnal sleep period in the luteal phase compared with the follicular phase, which they suggest may reflect coupling between body temperature and REM sleep.

    “Shechter, and colleagues (2010)[74] also found reduced REM sleep in naps during the habitual nocturnal sleep period in the luteal phase compared with the follicular phase, which they suggest may reflect the coupling between body temperature and REM sleep.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [74] source

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  • May combine two claims.

    Premisecitation
    § Methods

    In an overnight cognitive performance study, neurobehavioral performance was worse in the follicular phase, and Grant et al. found a significant inverse correlation between core body temperature and attentional failures in naturally-cycling women.

    “In a study of cognitive performance overnight, in which neurobehavioral performance was worse in the follicular phase, Grant and colleagues [76],found a significant inverse correlation between core body temperature and attentional failures in the naturally-cycling women.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [76] Grant LK, 2019, Sleep

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Shechter and colleagues argue that the delay found by Cagnacci and colleagues in the luteal phase could be a consequence of the effects of bright light on the core body temperature rhythm, since dim light conditions were not maintained across the experiment.

    “Shechter and colleagues [74] argue that the delay found by Cagnacci and colleagues in the luteal phase could be a consequence of the effects of bright light on the core body temperature rhythm, since dim light conditions were not maintained across the experiment.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [74] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    Most studies have compared core body temperature rhythms in the luteal and follicular phases, but a change in body temperature also may occur around ovulation, albeit a smaller change that is not always detected.

    “Most studies have compared core body temperature rhythms in the luteal and follicular phases, but a change in body temperature also may occur around the time of ovulation, albeit a smaller change that is not always detected.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    In 1945, Halbrecht observed that the "progestin phase" (luteal phase) was preceded by a slight but constant fall in basal core body temperature (oral or rectal) in some women in whom body temperature was monitored.

    “In 1945, Halbrecht observed that the “progestin phase” (luteal phase) was preceded by a slight but constant fall in basal core body temperature (oral or rectal) in some of the women in which body temperature was monitored [56].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [56] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Studies measuring skin temperature for shorter intervals at rest or during exercise have produced mixed results for menstrual cycle effects, with some showing increased skin temperature and others no difference in the luteal relative to the follicular phase.

    “Studies that have measured skin temperature for shorter time intervals either at rest or during exercise have produced mixed results for menstrual cycle effects, with some showing increased skin temperature and others no difference in the luteal relative to the follicular phase [reviewed in 36].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [36] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Distal skin temperature was out of phase with core body temperature, with minimum core body temperature recorded at a similar time as maximum distal skin temperature in both menstrual phases.

    “distal skin temperature was out of phase with core body temperature, with minimum core body temperature recorded at a similar time (follicular: 0434 h ± 0025; luteal: 0420 h ± 0022) as maximum distal skin temperature (follicular: 0314 h ± 0057; luteal: 0423 h ± 0104) in both menstrual phases [83].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [83] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    In women with multiple follicle development induced with FSH injections from day 8 onwards, resulting in a prolonged estrogen surge, the entire 24-h core body temperature curve was shifted lower, with no change in amplitude or phase, in association with a low progesterone:estrogen ratio just before ovulation.

    “In a study of women with multiple follicle development induced with FSH injections from day 8 onwards, which results in a prolonged estrogen surge, the entire 24-h core body temperature curve was shifted lower, with no change in amplitude or phase, in association with a low progesterone:estrogen ratio just before ovulation [67].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [67] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    There was no menstrual cycle phase effect on the distal-proximal skin temperature gradient, suggesting no change in internal heat conduction across the menstrual cycle.

    “There was no menstrual cycle phase effect on the distal-proximal skin temperature gradient, suggesting no change in internal heat conduction across the menstrual cycle [82]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [82] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    Variability in findings on the phase of the core body temperature rhythm could be explained by masking of the endogenous rhythm by factors such as environmental light, activity, sleep, and posture, as well as by different methods and indicators of phase.

    “This variability in findings could be explained by masking of the endogenous core body temperature rhythm by factors such as environmental light, activity, sleep, and posture [78,81], as well as by the application of different methods and indicators of phase.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [78] source

      Not checked in the free run.

    • cites [81] Czeisler CA, 1999

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning
    § Methods

    Differences between study results can possibly be explained by differences in the progestin used or ratio of progestin to estradiol.

    “Possibly, differences between study results can be explained by differences in the progestin used or ratio of progestin to estradiol.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation
    § Methods

    An increase in heart rate (3% to 5%) in the luteal phase relative to the follicular phase is evident, particularly during sleep, and is associated with a decrease in vagal activity.

    “An increase in heart rate (3% to 5%) in the luteal phase relative to the follicular phase is evident, particularly during sleep [84,86,94], and is associated with a decrease in vagal activity [94].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [84] source

      Not checked in the free run.

    • cites [86] source

      Not checked in the free run.

    • cites [94] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    Estrogen has a temperature-lowering effect that can temporarily oppose the effect of progesterone, although progesterone's hyperthermic effect is dominant.

    “In summary, estrogen has a temperature-lowering effect that can temporarily oppose the effect of progesterone, although progesterone’s hyperthermic effect is dominant [60].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [60] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Studies of 24-h body temperature rhythms have shown that women taking oral contraceptives in the active phase have body temperatures similar to those of women in the luteal phase, which are higher than those of men and women in the follicular phase.

    “Further, studies of 24-h body temperature rhythms have shown that women taking oral contraceptives in the active phase of the contraceptive regime have body temperatures similar to those of women in the luteal phase, which are higher than those of men and women in the follicular phase [69,78,79].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [69] source

      Not checked in the free run.

    • cites [78] source

      Not checked in the free run.

    • cites [79] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Israel and Schneller found that oral administration of a progestogen alone (pregneninolone, high dose: 4 daily doses of 20 mg for a total dose of 80 mg) in ovariectomized women increased basal rectal temperature by 0.2°C to 0.3°C within 24 h in 19 of 22 trials; temperatures declined within 48 h after progestogen withdrawal.

    “Israel and Schneller [60] found that oral administration of a progestogen alone (pregneninolone, high dose: 4 daily doses of 20 mg for a total dose of 80 mg) in ovariectomized women increased basal rectal temperature by 0.2°C to 0.3°C within 24 h in 19 of 22 trials; temperatures declined within 48 h after progestogen withdrawal.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [60] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    The majority but not all studies find an increase in energy expenditure or basal metabolic rate of about 5% to 9% in the luteal phase.

    “The majority [29,108–113] but not all [114,115] studies find an increase in energy expenditure or basal metabolic rate of about 5% to 9% in the luteal phase.”
    Quote in the paperSubstantial claim0 of 9 sources checked
    • cites [29] source

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    • cites [108] source

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    • cites [109] source

      Not checked in the free run.

    • cites [110] source

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    • cites [111] source

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    • cites [112] source

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    • cites [113] source

      Not checked in the free run.

    • cites [114] source

      Not checked in the free run.

    • cites [115] source

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  • May combine two claims.

    Premisecitation
    § Methods

    The rise in core body temperature was still evident if progestogen followed ethinyl estradiol administration, and if estradiol and progestogen were administered simultaneously (although a higher progestogen dose was required to obtain the effect).

    “The rise in core body temperature was still evident if progestogen followed ethinyl estradiol administration, and if estradiol and progestogen were administered simultaneously (although a higher progestogen dose was required to obtain the effect) [60].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [60] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    A high dose of estradiol benzoate (1.5 mg) administered to women during the luteal phase lowered basal core body temperature, but the effect was temporary.

    “Also, while a high dose of estradiol benzoate (1.5 mg) administered to women during the luteal phase lowered basal core body temperature, the effect was temporary.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [60] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given
    § Methods

    Studies in women with natural menstrual cycles, which are observational, point strongly to the effects of progesterone and estrogen on body temperature regulation, with progesterone being responsible for the increase in core body temperature in the luteal phase.

    “Studies in women with natural menstrual cycles, which are observational, point strongly to the effects of progesterone and estrogen on body temperature regulation, with progesterone being responsible for the increase in core body temperature in the luteal phase.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The effects of exogenous progesterone and estrogen administration on core body temperature reflect the effects of endogenous progesterone and estrogen across the natural menstrual cycle.

  • May combine two claims.

    Interpretationcitation
    § Methods

    The findings show that progestin effectively increased core body temperature; however, when estrogen was administered with progestin, the effect was reversed.

    “These findings show that progestin effectively increased core body temperature; however, when estrogen was administered with progestin, the effect was reversed [107].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [107] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Progesterone's thermogenic effect is evident even at low doses (5 mg) in men, but higher doses are more likely to induce a consistent response.

    “Progesterone’s thermogenic effect is evident even at low doses (5 mg) in men [98] (Figure 3) but higher doses are more likely to induce a consistent response [60,98].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [98] source

      Not checked in the free run.

    • cites [60] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    The thermogenic effect of progesterone is evident in rats.

    “The thermogenic effect of progesterone is also evident in rats [100–102].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [100] source

      Not checked in the free run.

    • cites [101] source

      Not checked in the free run.

    • cites [102] Nieburgs H, 1948, J Clin Endocrinol Metab

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    Overall correlational data suggest some relationship between the rise in body temperature and sleep changes in the luteal phase, although reproductive steroids also act directly on sleep regulatory centers, so both direct and indirect effects may be in play.

    “Overall, correlational data suggest some relationship between the rise in body temperature and sleep changes in the luteal phase, although reproductive steroids also act directly on sleep regulatory centers [93], so it is likely that both direct and indirect effects may be in play.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [93] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning
    § Methods

    Given variability between studies in timing, formulations, and pharmacokinetics, there is likely variability in hormonal clearance rates and thus the duration of effect of exogenous hormones on core body temperature.

    “Given the variability between studies in timing of when the women were studied during the 7-day placebo phase, oral contraceptive formulations used, and variability in the pharmacokinetics of oral contraceptives, there is likely variability in the hormonal clearance rates, and thus the duration of effect of the exogenous hormones on core body temperature.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationcitation
    § Methods

    Estrogen levels in the patients treated with human menopausal gonadotropin were also higher (more than double that of the other treatment group), and estrogen may have depressed the thermogenic action of progesterone.

    “However, estrogen levels in the patients treated with human menopausal gonadotropin were also higher (more than double that of the other treatment group), and estrogen may have depressed the thermogenic action of progesterone [61].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [61] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    In well-trained athletes taking oral contraceptives chronically, exercise performance in the heat did not differ over the menstrual cycle, despite the endogenous changes in core body temperature over the cycle still being present.

    “In well-trained athletes taking oral contraceptives chronically, exercise performance in the heat did not differ over the menstrual cycle, despite the endogenous changes in core body temperature over the cycle still being present [144].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [144] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    As a result, core body temperature did not rise excessively during exercise in the heat in the luteal phase, nor did heart rate or perceived rating of exhaustion.

    “As a result, core body temperature did not rise excessively during exercise in the heat in the luteal phase, nor did their heart rate or perceived rating of exhaustion.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [142] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    With hormone suppression, resting energy expenditure was reduced (by 3.7%) and this reduction was prevented by estrogen therapy.

    “The second study also found that with hormone suppression, resting energy expenditure was reduced (by 3.7%) and this reduction was prevented by estrogen therapy [117].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [117] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    A significant increase in resting energy expenditure in the mid-luteal phase was found compared with the early follicular phase, and a reduction in resting energy expenditure in response to GnRH agonist therapy (which suppressed progesterone and estrogen).

    “In the first study, a significant increase in resting energy expenditure in the mid-luteal phase was found compared with the early follicular phase, and a reduction in resting energy expenditure in response to GnRH agonist therapy (which suppressed progesterone and estrogen) [109].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [109] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Lee et al. found that women had a higher sweating rate and skin blood flow in the luteal phase when exposed to heat.

    “In contrast, Lee and colleagues [127] found that women had a higher sweating rate and skin blood flow in the luteal phase when exposed to heat.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [127] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Methods

    Pivarnik et al. reported a slightly greater increase in rectal temperature in women exercising at 22°C in the luteal compared to the follicular phase, and a perception by the women that the exercise was harder in the luteal phase.

    “Pivarnik and colleagues [131] reported a slightly greater increase in rectal temperature in women exercising at 22°C in the luteal compared to the follicular phase, and a perception by the women that the exercise was harder in the luteal phase [131].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [131] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Despite the change in the threshold for sweating, the sweating rate and pattern of sweating at various cutaneous sites do not differ across the menstrual cycle.

    “Despite the change in the threshold for sweating, it has been reported that the sweating rate and pattern of sweating at various cutaneous sites do not differ across the menstrual cycle [122,125].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [122] source

      Not checked in the free run.

    • cites [125] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Methods

    For eight of the women, the increase ranged between 8% and 16%, however, two other women showed a decrease of 2%.

    “For eight of the women, the increase ranged between 8% and 16%, however, two other women showed a decrease of 2%.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [113] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Well-trained women have smaller changes in core body temperature over the menstrual cycle, associated with reduced ovarian hormone concentrations and fluctuation over the cycle.

    “Well-trained women also have smaller changes in core body temperature over the menstrual cycle, associated with reduced ovarian hormone concentrations and fluctuation over the cycle [143].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [143] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    In well-trained endurance athletes exercising in moderate heat during the mid-luteal phase, the body temperature threshold for heat loss responses was lower and the sensitivity of heat loss responses was higher compared to those of untrained athletes.

    “In well-trained endurance athletes exercising in moderate heat during the mid-luteal phase, the body temperature threshold for heat loss responses was lower and the sensitivity of heat loss responses was higher compared to those of untrained athletes [139].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [139] source

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  • May combine two claims.

    Premisecitation
    § Methods

    There were similar shifts in thermal perception, with the hand temperature at which women felt pleasant higher in the luteal phase and subjects less sensitive to cold sensation in the luteal phase.

    “It also had been reported previously that there were similar shifts in thermal perception, with the hand temperature at which women felt pleasant higher in the luteal phase [118] and subjects less sensitive to cold sensation in the luteal phase [119].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [118] Cunningham DJ, 1971, J de Physiologie

      Not checked in the free run.

    • cites [119] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    In subjects taking oral contraceptives in the same study, thermoregulatory responses to exercise were more uniform across the menstrual cycle with no changes in the dynamics of the sweating response.

    “In subjects taking oral contraceptives in the same study, thermoregulatory responses to exercise were more uniform across the menstrual cycle with no changes in the dynamics of the sweating response [138].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [138] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    During exercise in a hot and dry environment, body temperature appears to increase at the same rate in both phases of the menstrual cycle, such that the core temperature difference between the luteal and follicular phases at rest is maintained during steady-state exercise.

    “During exercise in a hot and dry environment, body temperature also appears to increase at the same rate in both phases of the menstrual cycle, such that the core temperature difference between the luteal and follicular phases at rest is maintained during stead-state exercise [123].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [123] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    In well-trained women exercising in the heat, exercise performance did not differ across the menstrual cycle, and high-intensity intermittent running in the heat was not influenced by the phase of the menstrual cycle.

    “In contrast, in well-trained women exercising in the heat, exercise performance did not differ across the menstrual cycle [135] and high-intensity intermittent running in the heat was not influenced by the phase of the menstrual cycle [136].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [135] source

      Not checked in the free run.

    • cites [136] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Administration of a progestin-only contraceptive (depot-medroxyprogesterone acetate) increased resting metabolic rate by, on average, 9% (with 9 of 13 women showing an increase) in association with an increase in body temperature 3 weeks later.

    “Administration of a progestin-only contraceptive (depot-medroxyprogesterone acetate) increased resting metabolic rate by, on average, 9% (with 9 of 13 women showing an increase) in association with an increase in body temperature (measurement not defined) 3 weeks later, which is when maximum concentration is expected [116].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [116] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    Together, these results support an association between sex steroid hormones and energy expenditure, and both progesterone and estrogen may contribute to this effect in the luteal phase.

    “Together, these results support an association between sex steroid hormones and energy expenditure. Both progesterone and estrogen may contribute to this effect in the luteal phase.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [109] source

      Not checked in the free run.

    • cites [117] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Cumulative heat storage at different exercise intensities in a hot, dry environment was the same in both phases of the menstrual cycle, and there was no difference in whole body heat loss over the menstrual cycle.

    “Cumulative heat storage at different exercise intensities in a hot, dry environment was the same in both phases of the menstrual cycle, and there was no difference in whole body heat loss over the menstrual cycle [32].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [32] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    In recreationally active females, endurance time to fatigue in hot, humid conditions and exercise tolerance time in a hot, dry environment were lower in the luteal phase compared to the follicular phase.

    “In recreationally active females, endurance time to fatigue in hot, humid conditions [140]) and exercise tolerance time in a hot, dry environment [132] were lower in the luteal phase compared to the follicular phase.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [140] Janse de Jonge XA, Thompson MW, Chuter VH, Silk LN, Thom JM. Exercise performance over the menstrual cycle in temperate and hot, humid conditions.Med Sci Sports Exerc. 2012;44:2190-2198. source

      Not checked in the free run.

    • cites [132] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Female reproductive hormones affect the peripheral mechanism of vasodilation, with differences in cutaneous vasodilation across the menstrual cycle, at least in some regions of the body.

    “Female reproductive hormones affect the peripheral mechanism of vasodilation, with differences in cutaneous vasodilation across the menstrual cycle, at least in some regions of the body [125].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [125] source

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Another study found that rectal temperature increased at a slightly greater rate in the follicular compared to the luteal phase in women exercising at 24°C, which the authors attributed to a greater gain for sweating in the luteal phase.

    “In contrast, another study found that rectal temperature increased at a slightly greater rate in the follicular compared to the luteal phase in women exercising at 24°C, which the authors attributed to a greater gain for sweating in the luteal phase [138].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [138] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    The excitatory effect of progesterone on warm-sensitive neurons in the POA is likely mediated by progesterone receptors induced by estrogen; induction of progesterone receptors in the preoptic area takes 24-30 h.

    “These results elegantly show that the excitatory effect of progesterone on warm-sensitive neurons in the POA is likely mediated by progesterone receptors induced by estrogen [156]; induction of progesterone receptors in the preoptic area takes 24–30 h [157].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [156] source

      Not checked in the free run.

    • cites [157] source

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  • May combine two claims.

    Premisecitation
    § Methods

    Intravenous injection of progesterone in rabbits inhibits the firing rate of warm-sensitive neurons and stimulates cold-sensitive neurons in the POA and anterior hypothalamus, with a short latency (6-20 min) implying a non-genomic action.

    “Second, intravenous injection of progesterone in rabbits inhibits the firing rate of warm-sensitive neurons and stimulates cold-sensitive neurons in the POA and anterior hypothalamus, with a short latency (6–20 min) implying a non-genomic action [154].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [154] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Methods

    Fever results when cytokines, such as interleukin-1β, interleukin-6 and tumor necrosis factor-α, released from leukocytes and other cells, induce the synthesis of cyclooxygenase-2, which results in increased prostaglandin synthesis; prostaglandin E2 acts on the hypothalamus to alter the set point for body temperature regulation.

    “Fever results when cytokines, such as interleukin-1β (IL-1 β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), released from leukocytes and other cells, induce the synthesis of cyclooxygenase-2, which results in increased prostaglandin synthesis. Prostaglandin E2 acts on the hypothalamus to alter the set point for body temperature regulation, leading to an increase in heat production,”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [145] Roth J, 2018

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Pro-inflammatory cytokines such as IL-1 and TNF mediate fever after an infection, principally through stimulation of prostaglandin synthesis, resulting in an increased set point.

    “Pro-inflammatory cytokines such as IL-1 and TNF mediate fever after an infection, principally through stimulation of prostaglandin synthesis, resulting in an increased set point [160].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [160] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Randomly-cycling female rats show a blunted febrile response compared to males when injected with the pyrogen lipopolysaccharide (LPS), possibly as a result of a reduced response of cytokine mediators of fever, including TNF-α and MIP-1α.

    “Randomly-cycling female rats show a blunted febrile response compared to males when injected with the pyrogen lipopolysaccharide (LPS), possibly as a result of a reduced response of cytokine mediators of fever, including TNF-α and MIP-1α [146].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [146] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Methods

    Progesterone has been shown to stimulate macrophages to produce IL-1 and some researchers have shown that IL-1 activity is increased after ovulation when progesterone is high, providing some support for the hypothesis that the rise in core body temperature in the luteal phase is similar to a fever.

    “Progesterone has been shown to stimulate macrophages to produce IL-1 [161] and some researchers [but not all, e.g. 162] have shown that IL-1 activity [159] is increased after ovulation when progesterone is high, providing some support for the hypothesis that the rise in core body temperature in the luteal phase is similar to a fever [159].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [161] Flynn A, 1984, Lymphokine Res

      Not checked in the free run.

    • cites [159] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    Neurons responded, on average, at 8.3 ± 6.0 min, and recovered after 30-40 min, indicating that the inhibitory effect of progesterone is rapid, and unlikely to be genomic.

    “Neurons responded, on average, at 8.3 ± 6.0 min, and recovered after 30–40 min, again indicating that the inhibitory effect of progesterone is rapid, and unlikely to be genomic.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [155] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § Methods

    In women in the luteal phase, in whom both progesterone and estrogen are present, the ratio of progesterone to estrogen is critical in determining whether the inhibitory or excitatory effect of progesterone on warm-sensitive neurons in the POA is dominant.

    “Putting these findings in the context of studies in women in the luteal phase, in whom both progesterone and estrogen are present, it seems possible that the ratio of progesterone to estrogen is critical in determining whether the inhibitory or excitatory effect of progesterone on warm-sensitive neurons in the POA is dominant.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [67] source

      Not checked in the free run.

    • Rests on an assumption: Findings from animal studies on progesterone's central thermoregulatory actions generalize to women.

  • May combine two claims.

    Interpretationcitation
    § Methods

    In association with the rise in core body temperature in the luteal phase, there is an increase in the threshold temperatures for sweating onset, cutaneous vasodilation, thermal comfort, and cold sensations, which likely reflects an orchestrated thermoregulatory response from the brain.

    “First, as described above, in association with the rise in core body temperature in the luteal phase, there is an increase in the threshold temperatures for sweating onset, cutaneous vasodilation, thermal comfort, and cold sensations (Figure 4), which likely reflects an orchestrated thermoregulatory response from the brain.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [29] source

      Not checked in the free run.

    • Rests on an assumption: Shifts in thermoeffector thresholds indicate a change in the regulated set point for core body temperature.

  • May combine two claims.

    Interpretationcitation
    § Methods

    This effect persisted even when a progesterone receptor antagonist was applied, suggesting that it is not mediated via progesterone receptors.

    “This effect persisted even when a progesterone receptor antagonist was applied, suggesting that it is not mediated via progesterone receptors.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [156] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Others have reported increased prostaglandin plasma concentrations in the luteal phase.

    “Others have reported increased prostaglandin plasma concentrations in the luteal phase [163].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [163] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Methods

    During a fever, core body temperature continues to be regulated but is actively defended at a higher level.

    “During a fever, core body temperature continues to be regulated but is actively defended at a higher level [9].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [9] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Marrone et al. showed in three animals that administration of progesterone directly into the POA increased colonic temperature by 0.5°C; four rats who received cholesterol administration as a control showed no consistent change in colonic temperature.

    “Third, Marrone and colleagues [101] showed in three animals that administration of progesterone directly into the POA increased colonic temperature by 0.5°C; four rats who received cholesterol administration as a control showed no consistent change in colonic temperature.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [101] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    This excitatory effect was not evident in slices from animals not pretreated with estrogen or in slices from animals treated with estrogen only 12 h prior, and the effect was blocked when a progesterone receptor antagonist was applied together with progesterone.

    “This excitatory effect was not evident in slices from animals not pretreated with estrogen or in slices from animals treated with estrogen only 12 h prior, and the effect was blocked when a progesterone receptor antagonist was applied together with progesterone.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [156] source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductcitation
    § Methods

    Of the only four cold-sensitive neurons studied, three were inhibited by progesterone and one was activated; this sample is too small to draw any conclusions about the actions of progesterone on cold-sensitive neurons.

    “Of the only four cold-sensitive neurons studied, three were inhibited by progesterone and one was activated; this sample is too small to draw any conclusions about the actions of progesterone on cold-sensitive neurons.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [155] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Treatment of ovariectomized female rats with estrogen and progesterone reduced blood levels of the cytokine IL-1β (but not IL-6) and the febrile response to LPS, compared to control ovariectomized female rats.

    “Treatment of ovariectomized female rats with estrogen and progesterone reduced blood levels of the cytokine IL-1β (but not IL-6) and the febrile response to LPS, compared to control ovariectomized female rats [147].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [147] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    Although mediators of the fever response in females and males do not differ, there is evidence, particularly from animals, that female reproductive hormones modulate the immune response and may affect the magnitude of the febrile response.

    “Although mediators of the fever response in females and males do not differ, there is evidence, particularly from animals, that female reproductive hormones modulate the immune response and may affect the magnitude of the febrile response.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation
    § Methods

    Chronic oral contraceptive use attenuates the sweating response, which may impair performance if athletes are unable to pace themselves appropriately.

    “Chronic oral contraceptive use, however, attenuates the sweating response, which may impair performance if athletes are unable to pace themselves appropriately [144].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [144] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    In human peripheral mononuclear cells, estrogen and progesterone exert an inhibitory effect on IL-1β mRNA synthesis and IL-1β release but not IL-6 secretion.

    “In human peripheral mononuclear cells, estrogen, and progesterone exert an inhibitory effect on IL-1 β mRNA synthesis and IL-1β release but not IL-6 secretion [148].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [148] Li ZG, Danis VA, 1993, Clin Exp Rheumatol

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationcitation
    § Methods

    Given the view that fever has an upper limit, one would expect to see a smaller increment in core body temperature in febrile women in the luteal phase compared to the follicular phase, possibly as a result of changes in cytokine responsiveness, such that core body temperature is similar at the peak of the fever in both phases.

    “Given the view that fever has an upper limit [149], one would expect to see a smaller increment in core body temperature in febrile women in the luteal phase compared to the follicular phase, possibly as a result of changes in cytokine responsiveness, such that core body temperature is similar at the peak of the fever in both phases.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [149] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    Following priming by estrogen, progesterone excites warm-sensitive neurons (via progesterone receptors), which would increase heat loss and reduce heat production.

    “Following priming by estrogen, however, progesterone excites warm-sensitive neurons (via progesterone receptors), which would increase heat loss and reduce heat production.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [156] source

      Not checked in the free run.

    • Rests on an assumption: Findings from animal studies on progesterone's central thermoregulatory actions generalize to women.

  • May combine two claims.

    Premisecitation
    § Methods

    Rutanen et al. reported a case where the patient had recurrent fevers associated with high progesterone during the luteal phase of the menstrual cycle, and upregulated cytokine levels across the entire menstrual cycle.

    “Rutanen and colleagues [150] reported a case where the patient had recurrent fevers associated with high progesterone during the luteal phase of the menstrual cycle, and upregulated cytokine levels across the entire menstrual cycle.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [150] Rutanen EM, 1993, J Clin Endocrinol Metab

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Basal body temperature measurement remains a popular way of retrospectively tracking ovulatory cycles.

    “Despite these and other limitations [reviewed in 64], basal body temperature measurement is simple and cheap [175] and, therefore, remains a popular way of retrospectively tracking ovulatory cycles.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [175] source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation
    § Methods

    Basal body temperature may be of use in confirming ovulation has occurred after the fact.

    “However, they suggest that basal body temperature may be of use in confirming ovulation has occurred after the fact.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [55] source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation
    § Methods

    A 48-h window is needed to confirm a basal core body temperature criterion because of a large number of false nadirs and temperature rises.

    “They concluded that basal core body temperature is an unreliable indicator of ovulation for three main reasons: (1) large variation in the interval between the core body temperature nadir or rise in temperature and ovulation; (2) the need for a 48-h window to confirm a basal core body temperature criterion because of a large number of false nadirs and temperature rises; (3) difficulty in interpr”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [55] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    Estrogen can modulate progesterone-related increases in body temperature through its actions in the POA and through peripheral vasodilation effects.

    “As emphasized by Charkoudian and Stachenfeld (2014) [3] in their seminal review, estrogen can modulate progesterone-related increases in body temperature through its actions in the POA and through peripheral vasodilation effects, meaning that the balance of these hormones is likely critical for thermoregulatory control.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing).

    Premisecitation
    § Methods

    Melatonin's hypothermic effect is centrally mediated via a reduction in the threshold for active vasodilation.

    “It has been suggested that melatonin’s hypothermic effect is centrally mediated via a reduction in the threshold for active vasodilation [166]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [166] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    The increase in warm-sensitive neuron firing facilitates heat loss and reduces heat production.

    “Application of estradiol to isolated preoptic tissue slices from male rats causes an increase in the firing rate of warm-sensitive neurons, facilitating heat loss and reducing heat production [16] (Table 2).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [16] Silva NL, 1986, Am J Physiol

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Resting metabolic rate is determined at the cellular level by processes related to mitochondrial activity.

    “Resting metabolic rate is determined at the cellular level by processes related to mitochondrial activity [116].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [116] source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation
    § Methods

    There is large variation in the interval between the core body temperature nadir or rise in temperature and ovulation.

    “They concluded that basal core body temperature is an unreliable indicator of ovulation for three main reasons: (1) large variation in the interval between the core body temperature nadir or rise in temperature and ovulation; (2) the need for a 48-h window to confirm a basal core body temperature criterion because of a large number of false nadirs and temperature rises; (3) difficulty in interpr”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [55] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning
    § Methods

    The action of these hormones on the vasomotor state in the periphery likely also feeds back to the hypothalamus to further modulate core body temperature.

    “The action of these hormones on the vasomotor state in the periphery likely also feeds back to the hypothalamus to further modulate core body temperature.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation
    § Methods

    Basal core body temperature is an unreliable indicator of ovulation.

    “They concluded that basal core body temperature is an unreliable indicator of ovulation for three main reasons: (1) large variation in the interval between the core body temperature nadir or rise in temperature and ovulation; (2) the need for a 48-h window to confirm a basal core body temperature criterion because of a large number of false nadirs and temperature rises; (3) difficulty in interpr”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [55] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    An effect of progesterone via thyroid hormone has been discounted.

    “Of note, an effect of progesterone via thyroid hormone has been discounted [168].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [168] source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationcitation
    § Methods

    The thermoregulatory mechanism of steroid hormones is probably distinct from a classic infection-induced fever.

    “The authors concluded that the thermoregulatory mechanism of steroid hormones is probably distinct from a classic infection-induced fever [164].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [164] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Methods

    Basal body temperature measurement is simple and cheap.

    “Despite these and other limitations [reviewed in 64], basal body temperature measurement is simple and cheap [175] and, therefore, remains a popular way of retrospectively tracking ovulatory cycles.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [175] source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation
    § Methods

    There is difficulty in interpreting basal core body temperature charts.

    “They concluded that basal core body temperature is an unreliable indicator of ovulation for three main reasons: (1) large variation in the interval between the core body temperature nadir or rise in temperature and ovulation; (2) the need for a 48-h window to confirm a basal core body temperature criterion because of a large number of false nadirs and temperature rises; (3) difficulty in interpr”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [55] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Skin temperature is influenced by many confounding factors, including environmental temperature, sensor design, and site of measurement.

    “As described above and reviewed elsewhere [176], skin temperature is influenced by many confounding factors, including environmental temperature, sensor design, and site of measurement.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [176] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    Melatonin's hypothermic effect may also involve a shift in the vasoconstrictor system control to a lower internal temperature.

    “and possibly also a shift in the vasoconstrictor system control to a lower internal temperature [167].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [167] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    KNDy neurons are thought to be involved in triggering hot flashes in peri- and post-menopausal women.

    “There is considerable interest in this group of neurons because they are thought to be involved in triggering hot flashes in peri- and post-menopausal women: KNDy neurons are hypertrophied post-menopause after estrogen withdrawal and ablation of these neurons reduces cutaneous vasodilatation and partially blocks the effects of estrogen on thermoregulation [169].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [169] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning
    § Conclusion

    Proper consideration of the menstrual cycle may reduce noise in experiments and aid researchers in detecting differences between treatments or groups, including in measurements of body temperature.

    “Indeed, proper consideration of the menstrual cycle may reduce noise in experiments and aid researchers in detecting differences between treatments or groups, including in measurements of body temperature.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation
    § Methods

    A pre-ovulatory temperature nadir was detected in only 41% of cycles in one study investigating wrist skin temperature, suggesting prospective determination of ovulation with this method was not robust.

    “One study that investigated the possibility of detecting a decrease in skin temperature (measured at the wrist) before ovulation revealed that a pre-ovulatory temperature nadir was detected in only 41% of cycles, suggesting that prospective determination of ovulation with this method was not robust [177].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [177] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    The Ovularing study found that 83.4% of cycles were biphasic.

    “− 83.4% of the cycles were biphasic.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [184] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning
    § Conclusion

    There is intricate circuitry linking the thermoregulatory and reproductive systems, with estrogen and progesterone interacting in complex ways to alter thermoregulation.

    “We now understand that there is intricate circuitry linking the thermoregulatory and reproductive systems, with estrogen and progesterone interacting in complex ways to alter thermoregulation.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisenone given
    § Conclusion

    The microcircuitry of how progesterone and estrogen interact in the brain to modify central thermoregulation as well as their effects in the periphery are not well understood.

    “The microcircuitry of how progesterone and estrogen interact in the brain to modify central thermoregulation as well as their effects in the periphery are not well understood, and further work is needed.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Methods

    The OvuSense device-predicted probability of conception per fertile day curve closely matched that of ultrasound/LH combination.

    “- Device-predicted probability of conception per fertile day curve closely matched that of ultrasound/LH combination.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [48] source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning
    § Methods

    Several commercial wearables have been investigated in preliminary studies, mostly by the company, and have shown promising results for detection of the fertile window based on tracking an upward shift in temperature after ovulation.

    “As outlined in Table 3, several of these devices have been investigated in preliminary studies, mostly by the company, and have shown promising results for the detection of the fertile window (encompassing ovulation) based on tracking an upward shift in temperature after ovulation.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation
    § Methods

    The Oura ring skin temperature was 0.30°C higher in the luteal phase versus the follicular phase and correlated with waking oral temperature.

    “- Skin T with device was 0.30°C higher in LP vs FP, and correlated with waking oral T.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [180] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    The Ava bracelet algorithm showed good performance (90% of cycles) in detecting the 6-day fertile window, with specificity of 0.93 and sensitivity of 0.81.

    “- Algorithm showed good performance (90% of cycles) in detecting 6-day fertile window, with specificity of 0.93 & sensitivity of 0.81.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [178] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    In the Ava study, skin temperature, heart rate and respiratory rate increased in the luteal phase.

    “- Skin T, HR and respiratory rate increased in LP.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [178] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given
    § Conclusion

    The rise in core body temperature during the luteal phase is a cardinal signal of an ovulatory menstrual cycle that is well recognized and easy to measure.

    “The rise in core body temperature during the luteal phase is a cardinal signal of an ovulatory menstrual cycle that is well recognized and easy to measure.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § Conclusion

    Male bias is evident in most fields of biological research, and particularly so in the field of neuroscience, where males outnumber females at a ratio of 5.5 to 1.

    “Male bias is evident in most fields of biological research, and particularly so in the field of neuroscience, where males outnumber females at a ratio of 5.5 to 1 [186].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [186] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation
    § Methods

    Multi-sensor data show promise for not only retrospectively identifying ovulatory cycles but potentially predicting the period when fertility is highest.

    “Applying a machine learning algorithm to data from multiple sensors (contained in a wrist bracelet) revealed good performance in detecting the 6-day fertile window, showing the promise of multi-sensor data being applied to not only retrospectively identify ovulatory cycles but potentially to predict the period when fertility is highest [178].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [178] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § Methods

    The Ava bracelet showed an upward shift in wrist skin temperature in 82% of cycles, with higher average skin temperature in the luteal phase than the early follicular phase.

    “- Showed an upward shift in wrist skin T in 82% of cycles, with higher average skin T in LP than early FP.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [177] source

      Not checked in the free run.

160 of 160

  • The paper relies on this without support.

    The effects of exogenous progesterone and estrogen administration on core body temperature reflect the effects of endogenous progesterone and estrogen across the natural menstrual cycle.

    “These findings are supported by studies that have investigated the direct effects of exogenous hormone administration on core body temperature, to determine the separate and combined effects of progesterone and estrogen.”

  • The paper relies on this without support.

    Findings from animal studies on progesterone's central thermoregulatory actions generalize to women.

    “There are several lines of evidence supporting a direct effect of progesterone on the preoptic area of the hypothalamus to inhibit heat loss mechanisms (i.e., raise the set point at which behavioral and autonomic thermoeffector pathways are activated) and/or increase heat production.”

  • The paper relies on this without support.

    Shifts in thermoeffector thresholds indicate a change in the regulated set point for core body temperature.

    “If core body temperature is regulated at a higher operating point during the luteal phase, one would expect to find shifts in the thresholds for heat- and cold-defense effector mechanisms across the menstrual cycle.”
3 of 3

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The fluctuations in core body and skin temperatures during the menstrual cycle are due to varying levels of estrogen and progesterone which cause shifts in all autonomic thermoregulatory thresholds (shivering, sweating and cutaneous vasodilation).

    “This is due to the varying levels of estrogen and progesterone which cause shifts in all autonomic thermoregulatory thresholds (shivering, sweating and cutaneous vasodilation) [87].”

    From Human thermal perception and time of day: A review (2021) · cites this paper as [87]

  • Menstrual phases modulate peripheral temperature readings.

    “Menstrual phases modulate peripheral temperature readings60, but the lack of contraceptive or menstrual cycle phase data precluded any further analyses.”

    From Diurnal rhythms of wrist temperature are associated with future disease risk in the UK Biobank (2023) · cites this paper as [60]

  • Compared to the follicular phase of menstrual cycle, the core body temperature measured in early morning is 0.3 to 0.7 °C higher in the luteal phase, attributed to the thermogenic effect of progesterone.

    “In comparison to the follicular phase of menstrual cycle, the core body temperature (CBT) measured in early morning is 0.3 to 0.7 °C higher in the luteal phase [ 89 , 90 ], which is attributed to the thermogenic effect of progesterone [ 91 ]”

    From Physiological Rhythms and Biological Variation of Biomolecules: The Road to Personalized Laboratory Medicine (2023) · cites this paper as [89]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Table 2 reference numbers disagree with its caption

    Minor

    Table 2 lists references 154 and 155 for the first and third data columns, respectively. Its caption attributes those columns to references 155 and 156.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 15

  1. Silva NL, 1986, Am J Physiol, 250, R625
  2. Keefe DL, 1985, Oxford RevReprod Biol, 7, 346
  3. Mitchell D, 1985, Physiologist, 28, 507
  4. Metcalf MG, 1983, N Z Med J, 96, 645
  5. Grant LK, 2019, Sleep, 54, 972
  6. Gao B, 1995, Am J Physiol, 268, R1365
  7. Driver HS, 1996, J Clin Endocrinol Metab, 81, 728
  8. Sagot JC, 1987, Am J Physiol, 252, R462
  9. Nieburgs H, 1948, J Clin Endocrinol Metab, 8, 622
  10. Cunningham DJ, 1971, J de Physiologie, 63, 236
  11. Stephenson LA, 1985, Am J Physiol, 249, R186
  12. Avellini BA, 1980, J Appl Physiol Respir Environ Exerc Physiol, 49, 254
  13. Li ZG, Danis VA, 1993, Clin Exp Rheumatol, 11, 157
  14. Rutanen EM, 1993, J Clin Endocrinol Metab, 76, 1594
  15. Flynn A, 1984, Lymphokine Res, 3, 1

Cited by

Sorted by citations

Related

Authors
Baker, F. C., Siboza, F., & Fuller, A.
Affiliations
  • SRI International (US)
  • University of the Witwatersrand (ZA)
Corresponding author
Baker, Fiona C.
ORCID
Venue
Temperature
Publisher
Informa UK Limited
Published
2020-03-22
Volume
7
Issue
3
Pages
226-262
ISSN
  • 2332-8940 (ISSN-L)
  • 2332-8959
DOI
10.1080/23328940.2020.1735927
PMC
PMC7575238
OpenAlex
W3012616340
Cited by
262
References
188
Citations by year
2026: 58 · 2025: 72 · 2024: 53 · 2023: 44 · 2022: 15 · 2021: 19 · 2020: 1
FWCI
2.52
Type
journal article
Language
en
Open access
Locations
  • Temperature (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
National Institutes of Health (RF1AG061355)
Topics
  • Health Sciences › Medicine › Physiology › Thermoregulation and physiological responses
  • Health Sciences › Medicine › Critical Care and Intensive Care Medicine › Thermal Regulation in Medicine
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
Keywords
core body temperature, menstrual cycle, luteal phase, follicular phase, progesterone, estrogen, thermoregulation, circadian rhythm, heat exposure, cold exposure, exercise thermoregulation, fever, oral contraceptives, wearable temperature sensors, ovulation prediction

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

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