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Cited by 1Thermoregulation and physiological responsesPhysical Activity and HealthCardiovascular and exercise physiology

Influence of habitual physical activity on cognitive performance of healthy young adults after passive heat exposure

Open access
Zhuo, Fuhai, Gaurani, Reubenjamin J., Low, Ivan C.C., Deshayes, Thomas A., Lee, Jason K.W., Cheung, Stephen S., Choo, Pei Ling, Tan, Xiang Ren·2026·Journal of Exercise Science & Fitness
DOI 10.1016/j.jesf.2025.200436PMC PMC12804366
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Abstract

Objective: Regular physical activity is positively associated with enhanced cognitive performance, whereas excessive heat stress may negatively impact cognition. The role of habitual physical activity on cognitive function under heat stress is unclear. Thus, we investigated the influence of physical activity status on the cognitive performance of healthy individuals after acute passive heat exposure. Methods: Our study involved non-randomised quasi-experimental controlled trials where 28 participants (active: n = 13, 4 females, less-active: n = 15, 5 females) underwent 45-min hot water immersion (HWI). Participants immersed their lower limbs in 42 °C water in a seated position for 15 min before they wore a disposable raincoat and continued immersion for 30 min. Estimated core temperature via non-invasive CORE sensor, heart rate, ratings of thermal sensation and thermal comfort were monitored. Pre- and post-immersion, the participants performed Stroop test and Iowa gambling task (IGT) to assess selective attention, executive function and decision-making. Results: = 0.247). During HWI, the heart rate profiles, and subjective ratings were not different between groups regardless of physical activity status. Both groups exhibited faster reaction times and preserved accuracies in the Stroop test post-HWI, with no performance differences between groups. Similarly, for IGT, both active and less-active groups exhibited improved net scores post-HWI with no differences between groups. Conclusion: When exposed to modest levels of heat strain (≤38.5 °C), both physically active and less-active groups did not show impairment in executive function and risk-taking behaviour.

AI snapshot

Written from the paper’s full text.

TL;DR

In healthy young adults, 45-min passive heat exposure via hot water immersion to modest hyperthermia (≤38.5 °C) did not impair cognitive performance; instead, both active and less-active groups showed faster Stroop reaction times and improved Iowa Gambling Task net scores. Habitual physical activity status did not modify these heat-induced cognitive changes.

Key findings

  • Both groups reached similar end estimated core temperature after hot water immersion (active: 38.5 ± 0.4 °C; less-active: 38.3 ± 0.4 °C; p = 0.247), with no group difference in Δ Est-Tcore (1.3 ± 0.4 °C vs. 1.1 ± 0.4 °C; p = 0.384).
  • Stroop reaction times improved pre-to-post heat exposure for congruent, incongruent, and neutral stimuli (pooled mean differences: −189 ms [−260, −117], −281 ms [−388, −174], −184 ms [−272, −96]; all p < 0.001), while accuracy remained high (>93%) and did not differ between groups (ΔRT p = 0.838; ΔACC p = 0.925).
  • Iowa Gambling Task net scores improved after immersion for both groups (pooled mean difference: +18, 95% CI [6, 30]; p = 0.004), with no main effect of physical activity status (p = 0.508); post-immersion progressive IGT scores also improved across 20-attempt periods (p = 0.006).
  • The active group had greater body mass loss (0.8 ± 0.5% vs. 0.3 ± 0.3%; p < 0.001) and higher whole-body sweat rate (24.9 ± 11.7 vs. 13.7 ± 7.4 ml/min; p = 0.005), despite no group differences in heart rate, mean arterial pressure, or subjective thermal ratings.

Methods

  • Non-randomised quasi-experimental controlled trial conducted August–December 2023; 28 healthy adults aged 21–35 years completed the study (active: n = 13, 4 females; less-active: n = 15, 5 females), classified by self-reported moderate/vigorous physical activity (>3 times/week and ≥250 min/week vs. ≤3 times/week and ≤150 min/week).
  • Participants underwent a 45-min dual-phase hot water immersion: lower limbs in 42 °C water for 15 min, then continued immersion for 30 min while wearing a disposable raincoat; estimated core temperature, heart rate, blood pressure, thermal sensation, and thermal comfort were monitored.
  • Pre- and post-immersion cognitive assessments used the Stroop test and Iowa Gambling Task; analyses included MANOVA, mixed-model two-way ANOVA with repeated measures, Bonferroni correction, and effect sizes, with significance set at p < 0.05.

Limitations

  • The authors state the heat strain was modest, likely limiting heat-related cognitive deficits; they suggest future studies use a higher core temperature threshold such as 38.8 °C.
  • The authors state they did not control for menstrual cycle phase in female participants, conducted cognitive tests only before and after heat exposure (possible order effect), and used CORE sensors rather than direct deep-body temperature measurement, with validity not confirmed for passive hot water immersion.
  • The authors state the findings are limited to young, healthy adults and may not generalize to older or vulnerable populations; the text also makes evident the small sample, non-randomised design, and self-reported physical activity classification as limitations.

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

Integrity signals

Registry

Crossref · 10.1016/j.jesf.2025.200436

Cites

58 of 58 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

16 of 37 cited sources checked · 9 supported · 0 flagged · accuracy not yet measured

  • Study design and conductcitation

    Studies have reported moderate-to-good same-day test-retest reliability (r = 0.36 to 0.61) for IGT.

    “Studies have reported moderate-to-good same-day test-retest reliability (r = 0.36 to 0.61) for IGT.36”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [36] Sullivan-Toole, 2022, Enhancing the psychometric properties of the Iowa gambling task using full generative modeling, Comput Psychiatr Psychol source
  • Premisecitation

    The whole body heat loss capacity was unlikely to be compromised by the menstrual phase.

    “Secondly, we did not control for the menstrual cycle of the female participants which could have influenced their baseline body temperatures but the whole body heat loss capacity was unlikely to be compromised by the menstrual phase.52,53”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [52] Notley, 2019, Menstrual cycle phase does not modulate whole body heat loss during exercise in hot, dry conditions, J Appl Physiol source
    • cites [53] Lei, 2017, Influence of menstrual phase and arid vs. humid heat stress on autonomic and behavioural thermoregulation during exercise in trained but unacclimated women, J Physiol source
  • Study design and conductcitation

    The change in cognitive performances from pre to post-heating in this study exceeds the typical learning gains and known coefficients of variation (∼8%; 3-7%) for Stroop test reaction time and IGT net score respectively.

    “However, based on practice gains reported in literature, the change in cognitive performances from pre to post-heating in our study exceeds the typical learning gains and known coefficients of variation (∼8 %; 3–7 %) for Stroop test reaction time and IGT net score respectively.54, 55, 56, 57”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [54] Najenson, 2025, Practice makes better? The influence of increased practice on task conflict in the Stroop task, Mem Cognit source

      The Results (page unavailable) report that Stroop reaction times decreased across practice sessions, supporting the claim that practice can improve Stroop performance. The paper does not establish a typical 8% learning gain or coefficient of variation, and it does not address IGT net scores or the cited study’s pre- to post-heating change. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [55] Pilli, 2013, A computerized stroop test for the evaluation of psychotropic drugs in healthy participants, Indian J Psychol Med source

      The Results report interday reproducibility of Stroop reaction time with a coefficient of variation below 10%, broadly consistent with the cited ∼8% figure. The paper does not give an 8% value, quantify typical learning gains, or address IGT net scores or their 3–7% variation; it also cannot establish whether the citing study’s pre- to post-heating change exceeded those benchmarks. Page numbers are unavailable in our copy. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [56] Waters-Wood, 2012, Failure to learn from repeated mistakes: persistent decision-making impairment as measured by the iowa gambling task in patients with ventromedial prefrontal cortex lesions, J Int Neuropsychol Soc source
  • Findingown data

    There was no difference in the magnitude of reaction time change (Δ RT) for congruent, incongruent and neutral stimuli after HWI between active and less-active participants.

    “For between-group comparisons, there was no difference in the magnitude of RT change (Δ RT) for congruent, incongruent and neutral stimuli after HWI between active and less-active participants (F3,24 = 0.282, p = 0.838, Wilks' Λ = 0.966; Fig. 3A).”
    Quote in the paperSubstantial claim
  • Findingown data

    The active group had a higher mean whole body sweat rate (24.9 ± 11.7 ml/min) compared with the less-active group (13.7 ± 7.4 ml/min; p = 0.005).

    “The active group had a higher mean whole body sweat rate (24.9 ± 11.7 ml/min) when compared with the less-active group (13.7 ± 7.4 ml/min; p = 0.005, g = 1.166).”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. 25
  • May combine two claims. 27

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Sample size was determined a priori to detect significant change based upon findings on cognitive performance changes in a previous study involving healthy participants exposed to passive heat in a hot environmental chamber (50 °C, 50 % relative humidity) as compared to normothermic control in temperate (25 °C, 50 % relative humidity) condition.

    “Sample size was determined a priori to detect significant change based upon the findings on cognitive performance changes in a previous study involving healthy participants exposed to passive heat in a hot environmental chamber (50 °C, 50 % relative humidity) as compared to normothermic control in temperate (25 °C, 50 % relative humidity) condition.37”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [37] Gaoua, 2018, Effect of passive hyperthermia on working memory resources during simple and complex cognitive tasks. Original research, Front Psychol source

  • May combine two claims.

    Premisecitation

    Firefighters exposed to high temperatures show a decline in vigilance and cognitive flexibility, and soldiers in hot desert environment (42-43 °C) show reduced sustained attention and executive function.

    “Additionally, other studies have reported a decline in vigilance and cognitive flexibility in firefighters exposed to high temperatures,12 and reduced sustained attention and executive function in soldiers in hot desert environment (42–43 °C).13”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [12] Thompson, 2023, Do extreme temperatures affect cognition? A short review of the impact of acute heat stress on cognitive performance of firefighters, Front Psychol source

      The review’s “Extreme heat impairs cognition” section reports impaired firefighter performance on continuous performance tests, which assess attention, after a live-fire exercise. It does not report a decline in cognitive flexibility, and the Discussion says firefighter findings are mixed. The soldiers claim has a separate citation in the citing sentence and is not assessed here; page numbers are unavailable in our copy. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [13] Saini, 2017, Cognitive deficits due to thermal stress: an exploratory study on soldiers in deserts, Med J Armed Forces India source

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

    Premisecitation

    Environmental thermal stress impacts cognitive functions including memory, attention and processing speeds of older adults above 60 years, especially those with lower levels of physical activity.

    “In a separate study,7 it was found that environmental thermal stress similarly impacts cognitive functions including memory, attention and processing speeds of older adults above 60 years, especially those with lower levels of physical activity.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [7] Trezza, 2015, Environmental heat exposure and cognitive performance in older adults: a controlled trial, Age (Dordr) source

      The Results (page unavailable) report that heat exposure worsened memory and reaction-time scores in the higher-humidity subgroup, while participants with lower physical activity showed a significant decline in sustained attention. The paper found no significant cognitive difference for the full sample, and memory and processing-speed declines were not established specifically for the less-active subgroup. The claim omits these conditions and overgeneralizes the affected functions. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

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

    Premisecitation

    Habitual physical activity promotes higher fitness level, which is associated with better academic performance, cognitive performance and cognitive control in adolescents.

    “Habitual physical activity promotes higher fitness level,16 which has been associated with better academic performance,17 cognitive performance18 and cognitive control19 in adolescents.”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites [16] Júdice, 2017, Sedentary patterns, physical activity and health-related physical fitness in youth: a cross-sectional study, Int J Behav Nutr Phys Activ source

      Citation 16 attaches to the physical-activity–fitness clause, not the academic or cognitive outcomes cited separately. The Conclusions say that promoting at least moderate-intensity activity is likely to improve fitness in youth, but the Strengths and limitations section says the cross-sectional data cannot establish causality. Thus, the source supports an association and a qualified prediction, not the unqualified causal wording “promotes.” (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [17] Ruiz-Ariza, 2017, Influence of physical fitness on cognitive and academic performance in adolescents: a systematic review from 2005–2015, Int Rev Sport Exerc Psychol source
    • cites [18] Hogan, 2013, The interactive effects of physical fitness and acute aerobic exercise on electrophysiological coherence and cognitive performance in adolescents, Exp Brain Res source

  • May combine two claims.

    Premisecitation

    Prolonged exposure to work-related heat stress impairs cognitive performance, with increased response times and elevated error rates during Stroop and Continuous Performance tests.

    “In the occupational context, prolonged exposure to work-related heat stress impairs cognitive performance where workers’ response times were found to be increased with an elevated rate of errors during the Stroop test and Continuous Performance test.3,8”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [3] Mazloumi, 2014, Evaluating effects of heat stress on cognitive function among workers in a hot industry, Health Promot Perspect source

      The Results (page not provided) report increased reaction time on Stroop test 3 and more errors on Stroop tests 1–3 among heat-exposed workers. The Methods describe testing before and during a work shift, not prolonged exposure, and the study used Stroop tests rather than a Continuous Performance test. (LLM, conf=0.90)

      Experimental — accuracy not yet measured
    • cites [8] Rastegar, 2022, Evaluating the effect of heat stress on cognitive performance of petrochemical workers: a field study, Heliyon source

      The Results and Conclusion report increased response time and commission errors on the Continuous Performance Test among petrochemical workers exposed to heat across a shift. The Methods identify the tests used as CPT and N-back, not Stroop, so this source does not support the Stroop-test portion of the claim. Page numbers are unavailable in our copy. (LLM, conf=0.89)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Regular exercise stimulates neurogenesis, cerebral angiogenesis, synaptogenesis in cerebral structures and improves cerebrovascular reserve, which support better brain function.

    “Regular exercise stimulates neurogenesis,22 cerebral angiogenesis,23 synaptogenesis in cerebral structures and improves cerebrovascular reserve,24 which support better brain function.”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [22] Ballard, 2017, Exercise makes your brain bigger: skeletal muscle VEGF and hippocampal neurogenesis, J Physiol source
    • cites [23] Morland, 2017, Exercise induces cerebral VEGF and angiogenesis via the lactate receptor HCAR1, Nat Commun source
    • cites [24] Davenport, 2012, Cerebrovascular reserve: the link between fitness and cognitive function?, Exerc Sport Sci Rev source

  • May combine two claims.

    Premisecitation

    Given the acceptable reliability, CORE sensors can be used to assess group mean responses but not for individualised accuracy.

    “Given the acceptable reliability,58 CORE sensors can be used to assess group mean responses but not for individualised accuracy.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [58] Verdel, 2021, Reliability and validity of the CORE sensor to assess core body temperature during cycling exercise, Sensors source

  • May combine two claims.

    Findingown data

    The active group exhibited significantly higher whole body sweat rates and completed the immersion with greater body mass loss (0.5% more).

    “This was aligned to our results that the active group exhibited significantly higher whole body sweat rates and completed the immersion with greater body mass loss (0.5 % more).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    There was a main effect of time on the change of Toral for both groups, with no interaction effect and no main effect of physical activity status.

    “Similarly, for the Toral profile during immersion, there was a main effect of time on the change of Toral in both groups (F2.9,75.9 = 203.9, p < 0.001, η2p = 0.887) with no interaction effect (p = 0.078). Likewise, there was no main effect of physical activity status (F1,26 = 2.906, p = 0.100, η2p = 0.101) on the change of Toral across time”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    For IGT, both active and less-active groups exhibited improved net scores post-HWI with no differences between groups.

    “Similarly, for IGT, both active and less-active groups exhibited improved net scores post-HWI with no differences between groups.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    There was a main effect of time on the change of Est-Tcore for both groups, with no interaction effect and no main effect of physical activity status.

    “During immersion, there was a main effect of time on the change of Est-Tcore for both groups (F1.4,36.8 = 137.7, p < 0.001, η2p = 0.841) with no interaction effect (p = 0.518). However, there was no main effect of physical activity status (F1,26 = 0.904, p = 0.351, η2p = 0.034) on the change of Est-Tcore across time”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Active participants lost more body mass and were more dehydrated than less-active participants after HWI.

    “We demonstrated that both groups experienced similar thermal and cardiovascular strain after HWI, even though the active participants lost more body mass and were more dehydrated.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    There was no difference in all subjective ratings between active and less-active groups across time (p ≥ 0.486), indicating no differences in thermal sensation and thermal comfort during passive heating.

    “There was no difference in all subjective ratings between active and less-active groups across time (p ≥ 0.486), indicating no differences in thermal sensation (end RTS: 5.7 ± 1.0 vs. 5.6 ± 0.9) and thermal comfort (end RTC: 1.5 ± 1.0 vs. 1.8 ± 0.9) during passive heating, regardless of physical activity status.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    There was a main effect of time on the change of HR in both groups, with no interaction effect and no main effect of physical activity status.

    “For the HR profile during immersion, there was a main effect of time on the change of HR in both groups (F3.8,100.7 = 200.2, p < 0.001, η2p = 0.885) with no interaction effect (p = 0.632). There was no main effect of physical activity status (F1,26 = 0.284, p = 0.599, η2p = 0.011) on HR change across time”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    There was a main effect of time on the change of MAP in both groups, with no interaction effect and no main effect of physical activity status.

    “For blood pressure changes, there was a main effect of time on the change of MAP in both groups (F1.8,45.6 = 8.780, p < 0.001, η2p = 0.252) with no interaction effect (p = 0.205). There was no main effect of physical activity status (F1,26 = 1.266, p = 0.271, η2p = 0.046) on MAP changes across time”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Earlier studies have found that heat stress exposure results in impairment of executive function.

    “This is in contrast with the findings from earlier studies6,8 where heat stress exposure has resulted in the impairment of executive function.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [6] Shibasaki, 2017, Suppression of cognitive function in hyperthermia; from the viewpoint of executive and inhibitive cognitive processing, Sci Rep source

      Checked before — its earlier verdict is held back until a new check runs.

    • cites [8] Rastegar, 2022, Evaluating the effect of heat stress on cognitive performance of petrochemical workers: a field study, Heliyon source

      Checked before — its earlier verdict is held back until a new check runs.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductreasoning

    Immediately after HWI, participants performed post-intervention cognitive tests while remaining seated in the drained tub, with raincoat on but hood off, to ensure they did not lose heat rapidly during the tests.

    “Immediately after the HWI, participants performed the post-intervention cognitive tests while remaining seated in the drained tub, with raincoat on but its hood off. This ensured that participants did not lose heat rapidly during the tests.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Participation in regular physical activity is beneficial for cognition, with an inverse relationship between level of physical activity and likelihood of cognitive decline and dementia.

    “Participation in regular physical activity is known to be beneficial for cognition where an inverse relationship exists between the level of physical activity and the likelihood of cognitive decline and dementia.14,15”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [14] Paillard, 2015, Preventive effects of regular physical exercise against cognitive decline and the risk of dementia with age advancement, Sports Med Open source

      Checked before — its earlier verdict is held back until a new check runs.

    • cites [15] Law, 2020, Physical exercise attenuates cognitive decline and reduces behavioural problems in people with mild cognitive impairment and dementia: a systematic review, J Physiother source

      Checked before — its earlier verdict is held back until a new check runs.

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    The selected passive heating protocol allowed the study to investigate the independent effect of heat on cognition, compared to an exertional protocol which could be confounded by the effects of exercise.

    “The selected passive heating protocol allowed us to investigate the independent effect of heat on cognition, compared to an exertional protocol which could be confounded by the effects of exercise (e.g. increased arousal).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Fitter individuals with regular exercise training (not higher VO2max per se) are known to have superior vasodilatory responses, earlier onset of sweating and greater sweat rates and thus will experience a smaller rise in Tcore during uncompensable heat stress.

    “While this study did not directly assess participants’ aerobic capacity, fitter individuals with regular exercise training (not higher VO2max per se) are known to have superior vasodilatory responses, earlier onset of sweating and greater sweat rates and thus, will experience a smaller rise in Tcore during uncompensable heat stress.46,47”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [46] Ravanelli, 2021, A retrospective analysis to determine if exercise training-induced thermoregulatory adaptations are mediated by increased fitness or heat acclimation, Exp Physiol source
    • cites [47] Notley, 2020, Effect of aerobic fitness on the relation between age and whole-body heat exchange during exercise-heat stress: a retrospective analysis, Exp Physiol source

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

    Study design and conductnone given

    During immersion, participants were given fixed aliquots of ambient temperature water (1.5 g/kg/h fluid replenishment rate) every 15 min to avoid dehydration.

    “During the immersion process, participants were given fixed aliquots of ambient temperature water (1.5 g/kg/h fluid replenishment rate) to drink every 15 min to avoid dehydration.”
    Quote in the paperNot a substantial claim

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

    Study design and conductnone given

    Single data imputation was performed using linear interpolation taking reference from adjacent mean values to replace one missing Toral value (at 45 min).

    “To replace one missing Toral value (at 45 min) for analysis, single data imputation was performed using linear interpolation taking reference from adjacent mean values.”
    Quote in the paperNot a substantial claim

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

    Study design and conductnone given

    Mauchly's test was used to assess data sphericity, and the Greenhouse-Geisser correction was applied as necessary.

    “Mauchly's test was used to assess data sphericity, and the Greenhouse–Geisser correction was applied as necessary.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    These factors could reduce the ability to detect small group differences.

    “These factors could reduce the ability to detect small group differences.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Well-trained individuals demonstrate improved cerebral blood flow velocity and regulation, allowing them to maintain brain perfusion even with fluctuations in blood pressure under physical exertion or heat stress, a mechanism that is less efficient in untrained individuals.

    “For instance, well-trained individuals demonstrate improved cerebral blood flow velocity25 and regulation,26 allowing them to maintain brain perfusion even with fluctuations in blood pressure under physical exertion or heat stress, a mechanism that is less efficient in untrained individuals.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [25] Ainslie, 2008, Elevation in cerebral blood flow velocity with aerobic fitness throughout healthy human ageing, J Physiol source

      Checked before — its earlier verdict is held back until a new check runs.

    • cites [26] Korad, 2024, The effects of habitual resistance exercise training on cerebrovascular responses to lower body dynamic resistance exercise: a cross-sectional study, Exp Physiol source

      Checked before — its earlier verdict is held back until a new check runs.

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

    Premisecitation

    Heightened impulsivity and risk-taking behaviours are driven by warmer temperatures, leading to increased work errors.

    “Heightened impulsivity and risk-taking behaviours are driven by warmer temperatures, leading to increased work errors.10,11”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [10] Chang, 2017, Effects of heat stress on risk perceptions and risk taking, Appl Ergon source
    • cites [11] Alhadad, 2024, Effects of heat exposure and ice slurry ingestion on risk-taking behavior in healthcare workers, Med Sci Sports Exerc source

      Checked before — its earlier verdict is held back until a new check runs.

  • May combine two claims.

    Premisecitation

    Some aspects of cognitive function can be impaired by heat stress, resulting in poorer work performance, or increased occupational errors and workplace accidents when heat exposure becomes unavoidable.

    “Likewise, some aspects of cognitive function can be impaired by heat stress, resulting in poorer work performance, or increased occupational errors and workplace accidents when heat exposure becomes unavoidable.3”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [3] Mazloumi, 2014, Evaluating effects of heat stress on cognitive function among workers in a hot industry, Health Promot Perspect source

      Checked before — its earlier verdict is held back until a new check runs.

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

    Study design and conductnone given

    Participants were instructed to consume at least 500 mL of water 2 h before the experiment to ensure euhydration.

    “They were instructed to consume at least 500 mL of water 2 h before the experiment to ensure euhydration.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductcitation

    The Stroop test has been shown to be sensitive to alteration of cognitive functions and can identify deficits in selective attention or executive function under heat stress conditions.

    “The Stroop test has been shown to be sensitive to the alteration of cognitive functions and can identify deficits in selective attention or executive function (inhibitory control) under heat stress conditions.3,32”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [3] Mazloumi, 2014, Evaluating effects of heat stress on cognitive function among workers in a hot industry, Health Promot Perspect source

      Checked before — its earlier verdict is held back until a new check runs.

    • cites [32] Tan, 2024, Elevated brain temperature under severe heat exposure impairs cortical motor activity and executive function, J Sport Health Sci source

      Checked before — its earlier verdict is held back until a new check runs.

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

    Study design and conductnone given

    The passive nature of HWI removes the confounding effect of exercise in exertional protocol.

    “Also, the passive nature of HWI removes the confounding effect of exercise in exertional protocol.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Mild passive heating (+1.3 ± 0.2 °C in esophageal temperature) degraded executive function and inhibitory processing abilities during Go/No-go tasks in healthy young adults.

    “For instance, a study6 found that mild passive heating (+1.3 ± 0.2 °C in esophageal temperature) degraded executive function and inhibitory processing abilities during Go/No-go tasks in healthy young adults.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [6] Shibasaki, 2017, Suppression of cognitive function in hyperthermia; from the viewpoint of executive and inhibitive cognitive processing, Sci Rep source

      Checked before — its earlier verdict is held back until a new check runs.

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    Participants were instructed to abstain from exercise and refrain from ingesting alcoholic, caffeinated, and carbonated drinks one day prior to experiment to avoid confounding sympathetic activity and vasomotor effects that influence thermoregulation.

    “One day prior to experiment, participants were instructed to abstain from exercise and refrain from ingesting alcoholic, caffeinated, and carbonated drinks to avoid confounding sympathetic activity and vasomotor effects that influence thermoregulation.”
    Quote in the paperSubstantial claim

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

    Interpretationreasoning

    The lack of differences between groups could be due to interindividual differences in risk-taking tendencies and their individual abilities to adapt to the IGT test.

    “On the other hand, the lack of differences between groups could be due to interindividual differences in risk-taking tendencies and their individual abilities to adapt to the IGT test.”
    Quote in the paperNot a substantial claim

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

    Study design and conductown data

    All participants successfully completed 45 min of HWI without early termination.

    “all participants successfully completed 45 min of HWI without early termination in our study”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    A total of 28 participants (active: n = 13, less-active: n = 15) completed the study and were included for analysis.

    “A total of 28 participants (active: n = 13, age 24 ± 2 years, 4 females; less-active: n = 15, age 25 ± 3 years, 5 females) completed the study and were included for analysis”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Individual differences in training, heat acclimatisation and fitness status may affect physiological heat tolerance and thereby modulate resistance against cognitive deficits under heat stress.

    “While the two groups report different weekly MVPA durations, individual differences in training, heat acclimatisation and fitness status (e.g. type of physical activity, time spent outdoors and different exercise intensities) may affect their physiological heat tolerance and thereby modulate their resistance against cognitive deficits under heat stress.”
    Quote in the paperSubstantial claim

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

    Study design and conductnone given

    Bonferroni correction was applied post-hoc to correct for multiple comparisons.

    “To control the familywise error rate, Bonferroni correction was applied post-hoc to correct for multiple comparisons.”
    Quote in the paperNot a substantial claim

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

    Study design and conductnone given

    Shapiro-wilk test and Levene's test were conducted to assess data normality and equal variances.

    “Shapiro-wilk test and Levene's test were conducted to assess data normality and equal variances.”
    Quote in the paperNot a substantial claim

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

    Study design and conductreasoning

    Cognitive tests were only conducted before and after heat exposure, which may introduce an order effect.

    “Thirdly, cognitive tests were only conducted before and after heat exposure, which may introduce an order effect.”
    Quote in the paperNot a substantial claim

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

    Study design and conductnone given

    We did not control for the menstrual cycle of the female participants.

    “Secondly, we did not control for the menstrual cycle of the female participants which could have influenced their baseline body temperatures but the whole body heat loss capacity was unlikely to be compromised by the menstrual phase.52,53”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationnone given

    The current study focuses on young, healthy adults.

    “Lastly, it is crucial to note that the current study focuses on young, healthy adults.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductcitation

    CORE sensors are shown to perform well in tracking rates of change, thus the delta Tcore differences observed in this study between active and less-active participants are likely valid.

    “Furthermore, CORE sensors are shown to perform well in tracking rates of change,59 thus the delta Tcore differences observed in this study between active and less-active participants are likely valid.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [59] Jolicoeur Desroches, 2023, CORE™ wearable sensor: comparison against gastrointestinal temperature during cold water ingestion and a 5 km running time-trial, J Therm Biol source
    • Rests on an assumption: The CORE sensor's estimated core temperature is valid for passive heating via HWI.

  • May combine two claims.

    Study design and conductnone given

    The magnitude of rise in body temperature after HWI was modest, which could have limited the heat-related cognitive deficits.

    “Firstly, the magnitude of rise in body temperature after HWI was modest which could have limited the heat-related cognitive deficits.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The CORE sensor's estimated core temperature is valid for passive heating via HWI.

  • May combine two claims.

    Interpretationreasoning

    The active group's lower mean body mass corresponds to a smaller heat storage capacity which likely contributed to their faster Est-Tcore rise.

    “Furthermore, the active group had a lower mean body mass (difference of 6.7 kg albeit not statistically significant) corresponding to a smaller heat storage capacity which likely contributed to their faster Est-Tcore rise.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The CORE sensor's estimated core temperature is valid for passive heating via HWI.
44 of 44

  • The paper relies on this without support.

    The CORE body temperature sensor provides a valid estimate of core temperature.

    “Estimated core temperature (Est-Tcore) was assessed using a CORE body temperature sensor (greenTEG AG, Rümlang, Switzerland) fitted using a chest strap positioned below the sternum level with the sensor placed on the left side of chest.”

  • The paper relies on this without support.

    Self-reported physical activity frequency, duration, type, and sports background accurately classify participants as active or less-active.

    “The frequency and duration of moderate and vigorous physical activity performed per week, the type of exercise training, and the participants’ sports background were self-reported via an online survey.”

  • The paper relies on this without support.

    Participants complied with the instructions to abstain from exercise and from alcoholic, caffeinated, and carbonated drinks one day prior to the experiment.

    “One day prior to experiment, participants were instructed to abstain from exercise and refrain from ingesting alcoholic, caffeinated, and carbonated drinks to avoid confounding sympathetic activity and vasomotor effects that influence thermoregulation.”

  • The paper relies on this without support.

    Participants complied with the instruction to consume at least 500 mL of water 2 h before the experiment, ensuring euhydration.

    “They were instructed to consume at least 500 mL of water 2 h before the experiment to ensure euhydration.”

  • The paper relies on this without support.

    The non-randomised active and less-active groups are comparable in all relevant confounders except habitual physical activity.

    “The study was conducted as non-randomised quasi-experimental controlled trials where active and less-active participants were exposed to an acute heating intervention (hot water immersion; HWI) with cognitive assessments conducted pre- and post-HWI (Fig. 1).”

  • The paper relies on this without support.

    The cognitive tests performed immediately post-HWI while seated in the drained tub with raincoat on but hood off maintain body heat sufficiently so that cognitive performance reflects heat stress.

    “This ensured that participants did not lose heat rapidly during the tests.”

  • The paper relies on this without support.

    The CORE sensor's estimated core temperature is valid for passive heating via HWI.

    “However, it is less accurate than direct measurements of deep body temperature at thermally sensitive tissue sites (e.g. rectal or gastrointestinal temperatures), and its validity has yet to be confirmed for passive heating protocol via HWI.”
7 of 7

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. 2017, Threshold limit values for chemical substances and physical agents and biological exposure indices, Heat Stress and Strain

Cited by

Sorted by citations

Related

Authors
Zhuo, F., Gaurani, R. J., Low, I. C. C., Deshayes, T. A., Lee, J. K. W., Cheung, S. S., Choo, P. L., & Tan, X. R.
Affiliations
  • Singapore Institute of Technology (SG)
  • National University of Singapore (SG)
  • Université de Sherbrooke (CA)
  • Brock University (CA)
Corresponding author
Tan, Xiang Ren
ORCID
Venue
Journal of Exercise Science & Fitness
Publisher
Elsevier BV
Published
2026-01
Volume
24
Issue
1
Pages
200436
ISSN
1728-869X (ISSN-L)
DOI
10.1016/j.jesf.2025.200436
PMC
PMC12804366
OpenAlex
W7116665817
Cited by
1
References
56
Citations by year
2026: 1
FWCI
0.56
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Exercise Science & Fitness (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • PubMed Central (publishedVersion, cc-by-nc-nd)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
Santé
Topics
  • Health Sciences › Medicine › Physiology › Thermoregulation and physiological responses
  • Health Sciences › Medicine › Physiology › Physical Activity and Health
  • Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
Keywords
physical activity behavior, cognitive performance, heat stress, passive heat exposure, hot water immersion, executive function, selective attention, decision-making, risk-taking, Stroop task, Iowa Gambling Task, core body temperature, heart rate, thermal comfort, young adults

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 2026-11-05.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-11-05.

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