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Cited by 45Building Energy and Comfort OptimizationThermoregulation and physiological responsesCircadian rhythm and melatonin

Human thermal perception and time of day: A review

Open access
Vellei, Marika, Chinazzo, Giorgia, Zitting, Kirsi-Marja, Hubbard, Jeffrey·2021·Temperature
DOI 10.1080/23328940.2021.1976004PMC PMC8654484
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Abstract

The circadian clock regulates diurnal variations in autonomic thermoregulatory processes such as core body temperature in humans. Thus, we might expect that similar daily fluctuations also characterize human thermal perception, the ultimate role of which is to drive thermoregulatory behaviors. In this paper, we explore this question by reviewing experimental and observational thermal comfort investigations which include the “time of day” variable. We found only 21 studies considering this factor, and not always as their primary analysis. Due to the paucity of studies and the lack of a specific focus on time-of-day effects, the results are difficult to compare and appear on the whole contradictory. However, we observe a tendency for individuals to prefer higher ambient temperatures in the early evening as compared to the rest of the day, a result in line with the physiological decrease of the core body temperature over the evening. By drawing from literature on the physiology of thermoregulation and circadian rhythms, we outline some potential explanations for the inconsistencies observed in the findings, including a potential major bias due to the intensity and spectrum of the selected light conditions, and provide recommendations for conducting future target studies in highly-controlled laboratory conditions. Such studies are strongly encouraged as confirmed variations of human thermal perceptions over the day would have enormous impact on building operations, thus on energy consumption and occupant comfort.List of abbreviations: TSV: Thermal Sensation Vote; TCV: Thermal Comfort Vote; Tpref: Preferred Temperature; TA: Indoor Air Temperature; RH: Indoor Relative Humidity; Tskin: Skin Temperature; Tty: Tympanic Temperature; Tre: Rectal Temperature; Toral: Oral Temperature

AI snapshot

Written from the paper’s full text.

TL;DR

This review examines whether human thermal perception varies with time of day by synthesizing 21 experimental and observational thermal comfort studies alongside circadian thermoregulation physiology. It finds contradictory evidence but a tendency to prefer higher ambient temperatures in the early evening, and identifies light exposure, circadian individual differences, and menstrual phase as likely sources of inconsistency.

Key findings

Across 21 reviewed studies, the existence or absence of diurnal patterns in thermal perception could not be clarified; results appear “on the whole contradictory.” Among 15 experimental studies, 6 found no significant time-of-day differences, 6 found significant differences, 2 found significant differences only in male subjects, and 1 found differences only in heat-acclimatized subjects. Based on four studies, there is a tendency to prefer higher temperatures in the early evening compared to other times, consistent with the evening decrease in core body temperature, but at least four other studies contradict this. Observational set-point studies also predominantly show higher preferred temperatures in the evening, while questionnaire studies generally report warmer preferences later in the day, with Pollmann’s factory study contrasting. Only 3 of the 21 reviewed studies reported light exposure characteristics, and only in terms of intensity (lux); none of the observational studies measured light.

Methods

Narrative review with physiological background on thermoregulation and circadian rhythms. Literature search in Scopus between 1970 and 2021 using thermal perception and circadian/time-of-day search terms, limited to English peer-reviewed conference proceedings or journals and human subjects; automatic search yielded 111 papers, manual screening left 19, and reference-by-reference searching added 2, for 21 final studies. Included studies were classified as experimental (15, in climate chambers, mostly young participants aged 20–30) or observational (6, field studies), and findings were summarized study-by-study and in overview tables/figures.

Limitations

The paper states that only 21 studies considered time of day, often not as their primary analysis, making results difficult to compare and contradictory; it also states that no review had previously focused specifically on this dependency. The paper identifies major potential biases in the reviewed literature: uncontrolled inter-individual circadian phase/chronotype differences, insufficient control/reporting of light intensity and spectrum, uncontrolled menstrual phase in fertile women, overreliance on thermoneutral conditions, and failure to distinguish distal from proximal skin temperatures. Evident from the text: the review is qualitative, does not perform a meta-analysis or report pooled effect sizes, and its Scopus/English-language search may have excluded relevant non-English or non-indexed studies.

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Integrity signals

Registry

Crossref · 10.1080/23328940.2021.1976004

Cites

87 of 87 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 199 cited sources checked · 0 supported · 0 flagged

  • Findingreasoning

    No review paper to date has investigated the dependency of human thermal perception on the time of day.

    “To our knowledge, no review paper to date has investigated the dependency of human thermal perception on the time of day, although some past reviews on thermal comfort have offered cursory overviews of the subject [20,22–25].”
    Quote in the paperSubstantial claim
  • Findingnone given

    We identified a total of 15 experimental studies investigating daily variations in thermal perception.

    “We identified a total of 15 experimental studies investigating daily variations in thermal perception.”
    Quote in the paperNot a substantial claim
  • Findingreasoning

    The paper observes a tendency for individuals to prefer higher ambient temperatures in the early evening as compared to the rest of the day.

    “However, we observe a tendency for individuals to prefer higher ambient temperatures in the early evening as compared to the rest of the day, a result in line with the physiological decrease of the core body temperature over the evening.”
    Quote in the paperSubstantial claim
  • Findingcitation

    The temperature set-point variation analysis presented in three of the six observational studies showed that, in normal settings, people predominantly prefer higher temperatures in the evening compared to other times of the day.

    “The temperature set-point variation analysis presented in three of the six studies [79,80] showed that, in normal settings, people predominantly prefer higher temperatures in the evening compared to other times of the day.”
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    • cites [79] Hanmer C, 2019

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  • Findingcitation

    In two of the six studies finding significant differences, the differences were observed only in male subjects.

    “In addition, two out of the six studies finding significant differences observed these differences only in male subjects [19,72].”
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    Findingreasoning

    A total of 21 papers were finally considered for review.

    “A total of 21 papers were finally considered for review.”
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    Findingnone given

    The selected papers are either experimental or observational studies.

    “The selected papers are either experimental or observational studies and are presented in two separate sections.”
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    Findingnone given

    The reference by reference method found two additional publications.

    “The “reference by reference” method was then used to find two additional publications.”
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    Findingcitation

    The majority of the 15 reviewed experimental studies investigated responses to whole-body thermal exposures, while only two studies addressed localized thermal stimuli.

    “The majority of the 15 reviewed studies investigated responses to whole-body thermal exposures, while only two studies addressed localized thermal stimuli [71,72].”
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    Findingnone given

    Very few studies exist on time-of-day effects on thermal perception, and most do not consider time of day as the main influencing parameter.

    “However, very few studies exist on the topic, and most of them do not consider the “time of day” variable as the main influencing parameter in the evaluation of occupant thermal perception.”
    Quote in the paperSubstantial claim

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    Findingown data

    After manual screening, 19 papers were left.

    “After this manual screening process, we were left with 19 papers.”
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    Findingown data

    The automatic bibliographic search resulted in 111 papers.

    “The automatic bibliographic search resulted in 111 papers.”
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    Findingreasoning

    The results of the reviewed studies are difficult to compare and appear on the whole contradictory.

    “Due to the paucity of studies and the lack of a specific focus on time-of-day effects, the results are difficult to compare and appear on the whole contradictory.”
    Quote in the paperSubstantial claim

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    Findingnone given

    The reviewed experimental studies are equally distributed in terms of passive/active thermal assessment, with the most recent studies focusing on the active one.

    “The reviewed studies are equally distributed in terms of passive/active thermal assessment, with the most recent studies focusing on the active one.”
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    Findingnone given

    The 15 experimental studies were conducted in thermally-controlled climate chambers and included only young participants between 20 and 30 years old.

    “These studies were conducted in thermally-controlled climate chambers and included only young participants (between 20 and 30 years old).”
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    Findingcitation

    Among the 15 reviewed experimental studies investigating diurnal variations in thermal perception, two observed significant differences but were conducted only with male subjects.

    “two observed significant differences but were conducted only with male subjects [18,75]”
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    Findingnone given

    All the experimental studies were conducted in artificially illuminated climate chambers likely resulting in inconsistent spectral profiles.

    “Of note, all the experimental studies were conducted in artificially illuminated climate chambers likely resulting in inconsistent spectral profiles.”
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    Findingcitation

    Only three out of the 15 reviewed experimental studies reported the details of the light exposure and only in terms of intensity (lux).

    “However, only three out of the 15 reviewed experimental studies reported the details of the light exposure and only in terms of intensity (lux) [12,16,77,78].”
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    • cites [12] Nevins R, 1966, ASHRAE Trans

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    Findingnone given

    The reviewed experimental studies have adopted two different types of thermal assessment, either passive or active.

    “As we have seen in the section ‘Review of thermal comfort studies’ the reviewed experimental studies have adopted two different types of thermal assessment, either passive or active.”
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    Findingown data

    Among the 15 reviewed experimental studies investigating diurnal variations in thermal perception, six found no significant differences while nine found some significant differences.

    “Among the 15 reviewed experimental studies investigating diurnal variations in thermal perception, six found no significant differences in thermal perception with the time of day while nine found some significant differences.”
    Quote in the paperSubstantial claim

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    Findingown data

    Only three out of the 21 reviewed studies report the characteristics of the light exposure and only in terms of intensity (lux).

    “only three out of the 21 reviewed studies report the characteristics of the light exposure and only in terms of intensity (lux).”
    Quote in the paperSubstantial claim

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    Findingnone given

    Pollmann's study was conducted in a factory environment characterized by a fixed-temperature, but the other thermal comfort variables were not reported and might have varied throughout the day.

    “Pollmann’s study was conducted in a factory environment characterized by a fixed-temperature, but the other thermal comfort variables were not reported and might have varied throughout the day.”
    Quote in the paperNot a substantial claim

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    Findingown data

    In this paper, 21 studies (both observational and experimental) investigating diurnal variations of thermal perception were reviewed and some contradictory findings were found.

    “In this paper we reviewed 21 studies (both observational and experimental) investigating diurnal variations of thermal perception and found some contradictory findings.”
    Quote in the paperSubstantial claim

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    Premisecitation

    Changes in thermoregulatory effectors contribute to modification of core body and distal skin temperatures and affect sleep and waking behavior.

    “These changes in thermoregulatory effectors in turn contribute to the modification of core body and distal skin temperatures [4–6] and affect sleep and waking behavior [7,8].”
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    Interpretationreasoning

    A potential major bias in the reviewed findings is due to the intensity and spectrum of the selected light conditions.

    “By drawing from literature on the physiology of thermoregulation and circadian rhythms, we outline some potential explanations for the inconsistencies observed in the findings, including a potential major bias due to the intensity and spectrum of the selected light conditions”
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    Premisecitation

    A dynamic indoor temperature might contribute to a more healthy environment.

    “A dynamic indoor temperature might also contribute to a more healthy environment [21].”
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    Premisecitation

    Wang and Schweiker independently surveyed sources of diversity in human thermal perception and dedicated a paragraph to circadian rhythms related to variations in core body temperature, but none focused specifically on reviewing studies investigating dependency of thermal perception on time of day.

    “Wang [24] and Schweiker [25] independently surveyed sources of diversity in human thermal perception and dedicated a paragraph to circadian rhythms related to variations in core body temperature. However, none of these works focused specifically on reviewing studies investigating the dependency of thermal perception on the time of day.”
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    Premisecitation

    Time-varying indoor temperature set-points may help reduce energy use in buildings and promote their energy flexibility.

    “In fact, time-varying indoor temperature set-points may help reduce energy use in buildings and promote their energy flexibility [20].”
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    • cites [20] Mishra AK, 2016, Environ

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    Premisecitation

    The thermoregulatory system is diffuse, with thermoreceptors found in areas including the brain stem and spinal cord.

    “For example, thermoreceptors have been found in other areas, including the brain stem, and indeed in other central nervous system structures such as the spinal cord [30], underscoring the fact that the thermoregulatory system is diffuse [31].”
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    Premisecitation

    Humans are homeotherms, meaning their internal body temperature remains stable irrespective of environmental influence.

    “Humans, like nearly all mammals and avian species, are homeotherms (warm-blooded), meaning that their internal body temperature remains stable irrespective of environmental influence [26].”
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    Premisecitation

    Webb and te Kulve independently reviewed effects of light exposure on thermophysiology, thermal comfort, and health, and considered daily variations of thermophysiology and health, but did not review diurnal modifications of thermal perception.

    “Specifically, Webb [22] and te Kulve [23] independently reviewed the effects of light exposure on thermophysiology, thermal comfort, and health, and given that photic input is the primary synchronizer of the circadian clock, also considered daily variations of thermophysiology and health. However, diurnal modifications of thermal perception were not reviewed.”
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    Premisecitation

    More recent evidence contradicts findings from early thermal comfort studies, suggesting circadian variation plays a role in human thermal perception.

    “However, more recent evidence contradicts the findings from those early studies [18,19], suggesting that circadian variation plays a role in human thermal perception.”
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    Premisecitation

    During the night, the internal temperature thresholds for sweating and vasodilation are lower than during the day, while differences between morning and afternoon are smaller.

    “During the night, the internal temperature thresholds for sweating and vasodilation have been shown to be lower than during the day, while the differences observed between the morning and the afternoon are smaller [1–3,51].”
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    Premisecitation

    Circadian variation in physiological functions can be experimentally observed in constant routine or forced desynchrony laboratory protocols, which are the two gold standard methods for assessing circadian rhythmicity in humans.

    “Circadian variation in these physiological functions can be experimentally observed in either “constant routine” or “forced desynchrony” laboratory protocols, which are the two gold standard methods for assessing circadian rhythmicity in humans.”
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    Premisecitation

    Melatonin enhances heat loss by influencing peripheral vasodilatation, resulting in modification of core body and distal skin temperatures and regulation of sleep.

    “Melatonin enhances heat loss by influencing peripheral vasodilatation [54,55], which results in modification of core body and distal skin temperatures and regulation of sleep [7,8].”
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    Premisecitation

    The regulated variable in the thermoregulation system is an integrative temperature signal incorporating spatially distributed core body and skin temperatures.

    “Thus, the regulated variable in the thermoregulation system is an integrative temperature signal, which incorporates spatially distributed core body and skin temperatures [32].”
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    Premisecitation

    When exposed to a hot environment, the body reacts through active cutaneous vasodilation and sweating.

    “When a person is exposed to a hot environment (hyperthermia), the body reacts specifically to this condition through active cutaneous vasodilation and sweating [33,34].”
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    Premisecitation

    Light exposure, and in particular the light-dark cycle, is the primary synchronizer of the circadian clock to the 24-hour day, although sleep, physical activity, meal timing, and temperature can also synchronize daily rhythms.

    “Light exposure, and in particular the light-dark cycle, is the primary synchronizer of the circadian clock to the 24-hour day, although sleep, physical activity, meal timing, and temperature can also synchronize daily rhythms [40,41].”
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    • cites [40] Czeisler CA, Buxton OM, Khalsa SBS. Chapter 31: the human circadian timing system and sleep-wake regulation. In: Kryger MH, Roth T, Dement WC, editors. Principles and practice of sleep medicine. 4th ed. W.B. Saunders; 2005. p. 375–394. source

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    Premisecitation

    Given that skin warming appears to promote sleep, the preference for slightly cold thermal conditions during the day may help induce mild skin cooling and boost daytime alertness, wakefulness, and overall vigilance.

    “Furthermore, given that skin warming appears to promote sleep, the preference for slightly cold thermal conditions during the day may help to induce mild skin cooling and, hence, boost daytime alertness, wakefulness, and overall vigilance [53].”
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    Premisecitation

    Thermal comfort is the affective or hedonic component of thermal perception and is thought to be important for activating behavioral thermoregulatory responses in humans.

    “While thermal comfort is the affective or hedonic component of thermal perception and is thought to be important for activating behavioral thermoregulatory responses in humans, such as putting on/taking off clothing, changing activity level or posture, consuming hot/cold food or drinks, etc [36].”
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    Local changes in the hypothalamus can override temperature modification at the extremities, suggesting tight coupling of brain and body temperature.

    “Interestingly, although the external environment is the most likely cause for the initiation of thermoregulatory processes, local changes in the hypothalamus can override any temperature modification at the extremities of the body, suggesting a tight coupling of brain and body temperature [35].”
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    A lower core body temperature at night is a well-documented physiological phenomenon first published in 1842.

    “A lower core body temperature at night is a well-documented physiological phenomenon that was first published in 1842 [47].”
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    • cites [47] Gierse A. Quaemiam sit ratio caloris organii.1842.

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    Premisecitation

    Skin composition, specifically amount of hair, influences surface temperature; increased hair follicle amount augments thermal insulation and thermal stability of the skin.

    “Indeed, an increase in hair follicle amount will augment the organism’s capacity to thermally insulate and increase the thermal stability of the skin [32].”
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    Premisecitation

    The diurnal rhythm of proximal skin temperature is more complex but under real-life conditions appears to vary in phase with the distal skin temperature rhythm.

    “The diurnal rhythm of the proximal skin temperature (e.g., infraclavicular region, sternum) is more complex but, under real-life conditions, appears to vary in phase with the distal skin temperature rhythm [48,49].”
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    Premisecitation

    Daytime bright light may reduce the sensitivity to light in the evening or night.

    “Even though the effect of light history has not yet been reliably characterized, daytime bright light may reduce the sensitivity to light in the evening or night [61].”
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    Premisecitation

    The greatest melatonin suppressing effect has been observed at the wavelength of 424 nm.

    “The greatest melatonin suppressing effect has been observed at the wavelength of 424 nm [67].”
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    Premisecitation

    In the evening and early night, bright light, and in particular short wavelength (blue) light, induces phase-delays of the circadian rhythm and diminishes the decline in core body temperature and the increase in distal skin temperature.

    “In the evening and early night, bright light, and in particular short wavelength (blue) light, induces phase-delays of the circadian rhythm [56] and diminishes the decline in core body temperature and the increase in distal skin temperature [60].”
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    Premisecitation

    In the late night and early morning, light exposure results in phase advances and anticipates the increase in core body temperature and the decline in distal skin temperature, while no effect of light exposure on core body and distal skin temperatures has been observed in the afternoon.

    “In the late night and early morning, light exposure results in phase advances and anticipates the increase in core body temperature and the decline in distal skin temperature, while no effect of light exposure on core body and distal skin temperatures has been observed in the afternoon [58].”
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    Premisecitation

    Grivel & Candas found mean preferred temperatures highest between 17:00 and 18:00, and the difference of 1.5°C was significant.

    “Mean preferred temperatures were found to be highest between 17:00 and 18:00, and the difference (1.5°C) was significant.”
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    Interpretationcitation

    Pollmann's results appear to be in contrast with the conclusion that people preferred warmer temperatures in the afternoon, as participants indicated the constant temperature was warmer in the late afternoon, implying people prefer a colder temperature in the afternoons.

    “Pollmann’s results appear to be in contrast with this conclusion as the participants in his study indicated that the constant temperature to which they were exposed to for a day was warmer in the late afternoon compared to the rest of the day, implying that people prefer a colder temperature in the afternoons.”
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    Premisecitation

    Shoemaker & Refinetti found for male subjects the temperature thresholds for discomfort were significantly lower in the afternoon than at night, while for female subjects the difference was not significant.

    “For male subjects, the temperature thresholds at which the subjects began to feel thermally uncomfortable were found to be significantly lower in the afternoon than at night, while for female subjects the difference was not significant.”
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    Premisecitation

    Terai and colleagues found the lowest mean preferred temperature at 17:00, but the difference was not statistically significant.

    “The lowest mean preferred temperature was found at 17:00, but the difference was not statistically significant.”
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    Premisecitation

    Karyono found the difference between morning and afternoon neutral temperatures was 4°C in air temperature and 3.1°C in operative temperature.

    “The difference between morning and afternoon neutral temperatures was 4°C, in terms of air temperature, and 3.1°C in terms of operative temperature.”
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    • cites [82] Karyono TH, 2000, Environ

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    Premisecitation

    Fanger and colleagues found mean preferred temperatures slightly lower in the evening, but the difference of 0.2°C was not significant.

    “Mean preferred temperatures were found to be slightly lower in the evening, but the difference (0.2°C) was not significant.”
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    Premisecitation

    In Kakitsuba's summer experiment, male subjects' thermal sensation was found to be lowest in the evening and the difference compared to morning and afternoon was significant.

    “the male subjects’ thermal sensation was found to be lowest in the evening and the difference compared to morning and afternoon was significant.”
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    Premisecitation

    Hanmer and colleagues observed two higher temperature setpoints, one in the morning at 8:00 and one in the evening at 20:00, with the evening peak higher than the morning peak.

    “two higher temperature setpoints were observed, one in the morning (8:00) and the other in the evening (20:00), with the evening peak in temperature being higher than the morning peak.”
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    • cites [79] Hanmer C, 2019

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    Premisecitation

    In Kakitsuba's winter experiment, significant effects of time period on thermal sensation vote were observed for male but not female subjects, who felt coldest in the evening.

    “significant effects of the time period on the thermal sensation vote were observed for the male (but not for the female) subjects who felt coldest in the evening.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [18] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Huebner and colleagues found four temperature profiles: two with lower morning and higher evening temperatures, one flat profile, and one double-peak profile with a higher evening peak.

    “Their results highlighted the presence of four temperature profiles: two profiles with lower temperatures in the morning (6:00–7:30) and higher temperatures in the evening (21:00–23:30), one flat profile and one a “double-peak” profile (morning and evening peaks), with a higher peak in the evening (21:00–23:30).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [80] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The influence of light on thermophysiology has been mainly observed in the morning and evening, while in the afternoon no effect of light exposure on core body and distal skin temperatures was found.

    “Similarly, the influence of light on thermophysiology has been mainly observed in the morning and evening, while in the afternoon no effect of light exposure on core body and distal skin temperatures was found [58].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [58] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Shoemaker & Refinetti [75] and Kim & Tokura [74] found significant differences in thermal perception associated with the time since the last menstruation and the luteal/follicular phase, respectively.

    “Indeed, Shoemaker & Refinetti [75] and Kim & Tokura [74] found significant differences in thermal perception associated with the time since the last menstruation and the luteal/follicular phase, respectively.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [75] source

      Not checked in the free run.

    • cites [74] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Nonvisual photoreceptors in the retina, responsible for modulating circadian phase through circadian resetting, are most sensitive to shorter wavelengths of light (<480 nm).

    “However, as previously stated, nonvisual photoreceptors in the retina, which are responsible for modulating circadian phase through circadian resetting, are most sensitive to shorter wavelengths of light (<480 nm).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Vellei showed neutral temperatures have a daily trend with a minimum at around 14:00, and increase progressively in the rest of the day, indistinctively in the morning and evening.

    “it was further showed that the neutral temperatures have a daily trend with a minimum at around 14:00, and increase progressively in the rest of the day, indistinctively in the morning and evening.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [84] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Many exogenous differences (e.g., shift work, irregular sleeping and eating patterns, jetlag, irregular light exposure patterns) can be controlled for.

    “However, many of the exogenous differences such as those caused by shift work, irregular sleeping and eating patterns, jetlag, and irregular light exposure patterns, can be controlled for”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    The role of light as a circadian synchronizer strongly depends on the circadian phase (time of day at which light exposure occurs) and is characterized by non-linearity with respect to duration, spectrum, and intensity of light exposure.

    “In the previous sections we have highlighted that the role of light as a circadian synchronizer strongly depends on the circadian phase, i.e. on the time of day at which the light exposure occurs, and is characterized by non-linearity with respect to the duration, spectrum, and intensity of the light exposure.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The results of these studies could have been systematically compromised by the spectral effects of light, but this cannot be confirmed given that these characteristics were not reported.

    “Therefore, the results of these studies could have been systematically compromised by the spectral effects of light, but this cannot be confirmed given that these characteristics were not reported.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    In the early to mid-morning (06:00 to 10:00) and in the evening (18:00 to 22:00), humans experience a state of transition, which is a "heat gain" in the morning and a "heat loss" in the evening.

    “In fact, in the early to mid-morning (06:00 to 10:00) and in the evening (18:00 to 22:00), humans experience a state of transition [90], which is a “heat gain” in the morning (as the core body temperature climbs) and a “heat loss” in the evening (as the core body temperature drops).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [90] source

      Not checked in the free run.

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

    Premisecitation

    The salt recognition threshold exhibits a circadian variation with the lowest values recorded in the afternoon.

    “For example, the salt recognition threshold was found to exhibit a circadian variation with the lowest values recorded in the afternoon [88].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [88] source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    Light exposure in the evenings and mornings, especially to short wavelength blue and blue-enriched light, could compromise the measurements of diurnal variations in thermal perception by phase-shifting the circadian clock.

    “light exposure in the evenings and mornings, especially to short wavelength blue and blue-enriched light, should be avoided because this could compromise the measurements of diurnal variations in thermal perception by phase-shifting the circadian clock, either by advancing (in the morning) and/or by delaying (in the evening) it.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationcitation

    For experiments taking place in the evening, the bright illuminance (1450 lux) may have delayed circadian rhythms, reduced changes in core body and distal skin temperatures, and consequently changed subjects' thermal perception.

    “For experiments taking place in the evening, this bright illuminance may have delayed the circadian rhythms, reduced the changes in core body and distal skin temperatures [23,67], and consequently, also changed the subjects’ thermal perception.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [23] source

      Not checked in the free run.

    • cites [67] source

      Not checked in the free run.

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

    Premisecitation

    The recognition thresholds for sweet compounds also show a daily variation.

    “In addition, the recognition thresholds for sweet compounds also showed a daily variation [89].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [89] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Preference in the afternoon may be due to differences in thermal perception evaluation and data analysis, in the investigated populations and/or in different experimental design (including overlooked differences in metabolic rates due to varying levels of activities during the day).

    “preference in the afternoon may be due to differences in thermal perception evaluation and data analysis, in the investigated populations and/or in different experimental design (including overlooked differences in metabolic rates due to varying levels of activities during the day).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    The time course of distal skin temperature does not exactly follow the time course in proximal skin temperature and its fluctuation is always characterized by larger diurnal amplitudes.

    “As we have discussed in the previous sections, the time course of distal skin temperature does not exactly follow the time course in proximal skin temperature and its fluctuation is always characterized by larger diurnal amplitudes [6,49].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [6] source

      Not checked in the free run.

    • cites [49] source

      Not checked in the free run.

67 of 67

  • The paper relies on this without support.

    The ultimate role of thermal perception is to drive thermoregulatory behaviors.

    “the ultimate role of which is to drive thermoregulatory behaviors.”
    “the ultimate role of which is to drive thermoregulatory behavioral responses.”
1 of 1

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?

  • Commonly used features are supported by prior work to be relevant to the effects of DM.

    “commonly used features supported by prior work to be relevant to the effects of DM31–33,35–38,45,49”

    From Sleep and temperature data from wearable devices support noninvasive detection of diabetes mellitus in a large-scale, retrospective analysis (2026) · cites this paper as [33]

    The Discussion (Individual differences in circadian timing; Controlling for light) identifies chronotype, sleep schedules, and light exposure as relevant to detecting time-of-day effects on thermal perception. It does not establish that the citing document’s unspecified ‘commonly used features’ are relevant to the effects of DM, so that broader attribution cannot be verified from this source. (LLM, conf=0.68)

    Experimental — accuracy not yet measured

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.

  • Temperature count conflicts with the stated range and increments

    Minor

    Starting at 15.5°C and increasing by 0.56°C would require about 39 temperatures to reach 36.5°C, not 20.

  • Kim and Tokura initial conditions differ between table and text

    Minor

    Table 1 gives an initial air temperature of 23°C and relative humidity of 60%, while the study description gives 25.1°C and 50%.

  • Grivel and Candas initial conditions differ between table and text

    Minor

    Table 1 gives an initial air temperature of 25.1°C and relative humidity of 50%, while the study description gives 31°C and 40%.

  • Claim that all experimental participants were 20-30 conflicts with table

    Minor

    The text says the experimental studies included only participants aged 20-30, but Table 1 lists an age range beginning at 18 for Nevins and Rohles.

  • Huebner study duration differs between table and text

    Minor

    The description calls the observation period three months, whereas Table 2 dates it from mid-July 2007 to early February 2008, a span of roughly six and a half months.

5 of 5

Cites

Flagged first, then by citations

Research works printed but not linked: 5

  1. Nevins R, 1966, ASHRAE Trans, 72, 283
  2. Mishra AK, 2016, Environ, 109, 82
  3. Webb CG, 1961, Ann Occup Hyg
  4. Hanmer C, 2019, ECEEE 2019 summer study energy effic, 1377
  5. Karyono TH, 2000, Environ, 35, 77

Cited by

Sorted by citations

Related

Authors
Vellei, M., Chinazzo, G., Zitting, K.-M., & Hubbard, J.
Affiliations
  • Centre National de la Recherche Scientifique (FR)
  • Northwestern University (US)
  • Brigham and Women's Hospital (US)
  • École Polytechnique Fédérale de Lausanne (CH)
Corresponding author
Vellei, Marika
ORCID
Venue
Temperature
Publisher
Informa UK Limited
Published
2021-10-02
Volume
8
Issue
4
Pages
320-341
ISSN
  • 2332-8940 (ISSN-L)
  • 2332-8959
DOI
10.1080/23328940.2021.1976004
PMC
PMC8654484
OpenAlex
W3205400994
Semantic Scholar
5ac3f6dca061cdb1d58721f7c50e3f6301b97ad9
Cited by
45
References
87
Citations by year
2026: 7 · 2025: 11 · 2024: 11 · 2023: 11 · 2022: 5
FWCI
0.62
Type
journal article
Language
en
Open access
Licence
Locations
  • Temperature (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • HAL (submittedVersion, other-oa)
  • Infoscience (Ecole Polytechnique Fédérale de Lausanne) (submittedVersion, cc-by-nc-nd)
Funders
Marie Sklodowska-Curie (884556)
Topics
  • Physical Sciences › Engineering › Building and Construction › Building Energy and Comfort Optimization
  • Health Sciences › Medicine › Physiology › Thermoregulation and physiological responses
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
Keywords
thermal sensation, time of day, circadian rhythm, thermoregulation, thermal comfort, core body temperature, light conditions, indoor temperature, occupant comfort, building energy consumption

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.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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