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The advent of artificial intelligence (AI), particularly large language models (LLMs) like ChatGPT and Gemini, has significantly impacted the educational landscape, offering unique opportunities for learning and assessment. In the realm of written assessment grading, traditionally viewed as a laborious and subjective process, this study sought to evaluate the accuracy and reliability of these LLMs in evaluating the achievement of learning outcomes across different cognitive domains in a scientific inquiry course on sports physiology. Human graders and three LLMs, GPT-3.5, GPT-4o, and Gemini, were tasked with scoring submitted student assignments according to a set of rubrics aligned with various cognitive domains, namely "Understand," "Analyze," and "Evaluate" from the revised Bloom's taxonomy and "Scientific Inquiry Competency." Our findings revealed that while LLMs demonstrated some level of competency, they do not yet meet the assessment standards of human graders. Specifically, interrater reliability (percentage agreement and correlation analysis) between human graders was superior as compared to between two grading rounds for each LLM, respectively. Furthermore, concordance and correlation between human and LLM graders were mostly moderate to poor in terms of overall scores and across the pre-specified cognitive domains. The results suggest a future where AI could complement human expertise in educational assessment but underscore the importance of adaptive learning by educators and continuous improvement in current AI technologies to fully realize this potential. NEW & NOTEWORTHY The advent of large language models (LLMs) such as ChatGPT and Gemini has offered new learning and assessment opportunities to integrate artificial intelligence (AI) with education. This study evaluated the accuracy of LLMs in assessing an assignment from a course on sports physiology. Concordance and correlation between human graders and LLMs were mostly moderate to poor. The findings suggest AI's potential to complement human expertise in educational assessment alongside the need for adaptive learning by educators.

Purpose: Healthcare workers (HCWs) wearing personal protective equipment (PPE) experience physiological strain that can impair motor and psychological functions, potentially affecting patient care. We assessed the effects of heat exposure on maximal strength and risk-taking behavior among PPE-wearing HCWs and the efficacy of ice slurry to alleviate adverse effects., Methods: Seventeen HCWS completed two experimental trials in a crossover design, consuming 5 g·kg -1 of body mass of ambient drink (AMB) or ice slurry (ICE) before donning PPE and undergoing 2 h of simulated decontamination exercise (wet-bulb globe temperature (WBGT): 25.9°C ± 0.8°C, PPE microenvironment WBGT: 29.1°C ± 2.1°C). Body core temperature ( Tc ), heart rate (HR), chest skin temperature ( Tsk ), ratings of perceived exertion (RPE), thermal sensation (RTS), maximal voluntary contraction (MVC), risk-taking behavior (balloon analogue risk-taking task (BART)), and salivary cortisol were assessed., Results: Predrinking to postdrinking ∆ Tc was greater in ICE (-0.2°C ± 0.1°C) than AMB (-0.0°C ± 0.1°C, P = 0.003). Post-drinking RTS was lower in ICE (2.7 ± 1.2) than AMB (4.1 ± 0.4, P < 0.001). ICE and AMB had similar Tc and HR (both P > 0.05), but Tsk was lower in ICE than AMB ( P = 0.049). A lower MVC (30.3 ± 6.7 vs 27.4 ± 4.9 kg, P = 0.001) and higher BART-adjusted total pump count (472 ± 170 vs 615 ± 174 pumps, P = 0.017) was observed pretrial to posttrial in AMB but absent in ICE (both P > 0.05). Salivary cortisol was similar between trials ( P = 0.42)., Conclusions: Heat-exposed PPE-wearing HCWs had impaired maximal strength and elevated risk-taking behavior. This may increase the risk of avoidable workplace accidents that can jeopardize HCWs and patient care. Ice slurry ingestion alleviated these heat-related impairments, suggesting its potential as an ergogenic aid., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American College of Sports Medicine.)

Body core temperature (T c ) monitoring is crucial for minimizing heat injury risk. However, validated strategies are invasive and expensive. Although promising, aural canal temperature (T ac ) is susceptible to environmental influences. This study investigated whether incorporation of external auricle temperature (T ea ) into an ear-based T c algorithm enhances its accuracy during multiple heat stress conditions. Twenty males (mean ± SD; age = 25 ± 3 years, BMI = 21.7 ± 1.8, body fat = 12 ± 3%, maximal aerobic capacity (VO 2max ) = 64 ± 7 ml/kg/min) donned an ear-based wearable and performed a passive heating (PAH), running (RUN) and brisk walking trial (WALK). PAH comprised of immersion in hot water (42.0 ± 0.3 °C). RUN (70 ± 3%VO 2max ) and WALK (50 ± 10%VO 2max ) were conducted in an environmental chamber (T db  = 30.0 ± 0.2 °C, RH = 71 ± 2%). Several T c models, developed using T ac , T ea and heart rate, were validated against gastrointestinal temperature. Inclusion of T ea as a model input improved the accuracy of the ear-based T c algorithm. Our best performing model (T rf3 ) displayed good group prediction errors (mean bias error = - 0.02 ± 0.26 °C) but exhibited individual prediction errors (percentage target attainment ± 0.40 °C = 88%) that marginally exceeded our validity criterion. Therefore, T rf3 demonstrates potential utility for group-based T c monitoring, with additional refinement needed to extend its applicability to personalized heat strain monitoring., (© 2024. The Author(s).)

Pre-exercise passive heating attenuates muscle damage caused by eccentric exercise in rats where the induction of heat shock proteins (HSPs) confers a myoprotective effect. We investigated whether pre-exercise hot water immersion (HWI) confers similar benefits in humans. Eleven recreational male athletes were immersed in 41°C water up to 60 min or until rectal temperatures reached 39.5°C. After a 6 h rest, the participants performed an eccentric downhill run for 1 h at -4% gradient to induce muscle damage. An endurance capacity test at 75% VO 2max was conducted 18 h later. The control trial was similar except that participants were immersed at 34°C. Blood samples were collected to assess HSPs levels, creatine kinase, and lactate dehydrogenase activities. Plasma eHSP70 was higher post-immersion in HWI trials (1.3 ± 0.4 vs 1.1 ± 0.4; p  = 0.005). Plasma eHSP27 was higher before ( p  = 0.049) and after ( p  = 0.015) endurance test in HWI. Leukocytic p-HSP27 was increased 18 h after HWI (0.97 ± 0.14 vs 0.67 ± 0.11; p  = 0.04). Creatine kinase and lactate dehydrogenase activities were increased by 3-fold and 1.5-fold, respectively, after endurance test in HWI but did not differ across trials ( p  > 0.05). Mean heart rates were higher during eccentric run and endurance test in HWI as compared to control ( p  < 0.05). Endurance capacity was similar between trials (57.3 ± 11.5 min vs 55.0 ± 13.5 min; p  = 0.564). Pre-exercise heating increased the expression of plasma eHSPs and leukocytic p-HSP27 but did not reduce muscle damage nor enhance endurance capacity., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

Background: Excessive heat exposure can lead to hyperthermia in humans, which impairs physical performance and disrupts cognitive function. While heat is a known physiological stressor, it is unclear how severe heat stress affects brain physiology and function., Methods: Eleven healthy participants were subjected to heat stress from prolonged exercise or warm water immersion until their rectal temperatures (T re ) attained 39.5°C, inducing exertional or passive hyperthermia, respectively. In a separate trial, blended ice was ingested before and during exercise as a cooling strategy. Data were compared to a control condition with seated rest (normothermic). Brain temperature (T br ), cerebral perfusion, and task-based brain activity were assessed using magnetic resonance imaging techniques., Results: T br in motor cortex was found to be tightly regulated at rest (37.3°C ± 0.4°C (mean ± SD)) despite fluctuations in T re . With the development of hyperthermia, T br increases and dovetails with the rising T re . Bilateral motor cortical activity was suppressed during high-intensity plantarflexion tasks, implying a reduced central motor drive in hyperthermic participants (T re  = 38.5°C ± 0.1°C). Global gray matter perfusion and regional perfusion in sensorimotor cortex were reduced with passive hyperthermia. Executive function was poorer under a passive hyperthermic state, and this could relate to compromised visual processing as indicated by the reduced activation of left lateral-occipital cortex. Conversely, ingestion of blended ice before and during exercise alleviated the rise in both T re and T br and mitigated heat-related neural perturbations., Conclusion: Severe heat exposure elevates T br , disrupts motor cortical activity and executive function, and this can lead to impairment of physical and cognitive performance., (Copyright © 2023. Production and hosting by Elsevier B.V.)

Objectives: Compare the effects of ice slurry ingestion at low and normal doses on endurance capacity and exertional heat stress-induced gastrointestinal perturbations., Design: Randomised, cross-over design., Methods: Twelve physically active males completed four treadmill running trials, ingesting ice slurry (ICE) or ambient drink (AMB) at 2 g·kg -1 (Normal; N) or 1 g·kg -1 (Low; L) doses every 15-min during exercise and 8 g·kg -1 (N) or 4 g·kg -1 (L) pre- and post-exercise. Pre-, during and post-exercise serum intestinal fatty-acid binding protein ([I-FABP]) and lipopolysaccharide ([LPS]) concentrations were determined., Results: Pre-exercise gastrointestinal temperature (T gi ) was lower in L + ICE than L + AMB (p < 0.05), N + ICE than N + AMB (p < 0.001) and N + ICE than L + ICE (p < 0.001). Higher rate of T gi rise (p < 0.05) and lower estimated sweat rate (p < 0.001) were observed in N + ICE than N + AMB. Rate of T gi rise was similar at low dose (p = 0.113) despite a lower estimated sweat rate in L + ICE than L+AMB (p < 0.01). Time-to-exhaustion was longer in L + ICE than L + AMB (p < 0.05), but similar between N + ICE and N + AMB (p = 0.142) and L + ICE and N + ICE (p = 0.766). [I-FABP] and [LPS] were similar (p > 0.05)., Conclusions: L + ICE elicited a lower heat dissipation compensatory effect with similar endurance capacity as N + ICE. Ice slurry conferred no protection against exertional heat stress-induced gastrointestinal perturbations., Competing Interests: Declaration of interest statement None., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Practical classes are critical instructional activities in facilitating learning and motivation in health sciences education. With increasing pedagogical activities being conducted in virtual or remote settings, this study assessed how a remote practical assisted by physiological monitoring smartphone applications impacted student motivation and the achievement of intended learning outcomes in exercise physiology teaching. A total of 24 students (out of 30; 80%) were surveyed via a mixed-methods questionnaire containing 27 closed-ended, and 3 the traditional in-class practical in randomized order. Unpaired Student's t tests were performed for comparisons between interventions with a significance level set at P < 0.05. Students reported that both remote and in-class practicals strongly facilitated the achievement of learning outcomes. Self-reported scores for student satisfaction and perceived achievement of learning outcomes were similar between the two practical methodologies. Student motivation scores assessed using the Lab Motivation Scale revealed that students were more motivated during the remote practical, particularly in the effort domain ( P < 0.05). This was in line with the identified themes from the qualitative responses that indicated that the remote practical was more engaging than the in-person practical, with greater opportunities for experiential learning and class involvement being the main factors underlying these findings. Taken together, remote practicals can be critical aspects of a blended learning curriculum that encourages student engagement and experiential learning. With further advancements in physiological monitoring wearables and smartphone technologies, remote practicals can be potential alternatives to traditional in-person practicals in exercise physiology teaching. NEW & NOTEWORTHY Remote practical classes, supported by physiological monitoring smartphone applications, were assessed for their utility in facilitating learning and raising student motivation in health sciences education in this study. A comparison of remote practicals with traditional in-class practicals revealed that a remote practical is an effective method for reinforcing physiology learning objectives with the added advantage of increased student motivation. The added value of remote practicals may be attributed to more experiential learning opportunities and increased engagement levels.

Purpose: We compared the effectiveness of three field-based training programs, namely military-based heat acclimatization (MHA), isothermic conditioning (IC) and interval training (IT), in inducing physiological adaptations in tropical natives., Methods: Fifty-one untrained tropical native males (mean ± standard deviation: age, 25 ± 2 yr; body mass index, 23.6 ± 3.2 kg·m -2 ; body fat, 19% ± 5%; 2.4-km run time, 13.2 ± 0.9 min) donned the Full Battle Order attire (22 kg) and performed a treadmill route march heat stress test in an environmental chamber (dry bulb temperature, 29.9°C ± 0.5°C; relative humidity, 70% ± 3%). Heat stress tests were conducted before (PRE) and after (POST) a 2-wk training intervention consisting of either a MHA ( n = 17, 10 sessions of military-based heat acclimatization), IC ( n = 17, 10 sessions with target gastrointestinal temperature ( Tgi ) ≥ 38.5°C) or IT ( n = 17, six sessions of high-intensity interval training) program. Tgi , HR, mean weighted skin temperature ( Tsk ), physiological strain index (PSI) and thigh-predicted sweat sodium concentration ([Na + ]) were measured and analyzed by one-factor and two-factor mixed design ANOVA with a 0.05 level of significance., Results: Field-based IC induced a greater thermal stimulus than MHA ( P = 0.029) and IT ( P < 0.001) during training. Reductions in mean exercise Tgi (-0.2°C [-0.3°C, 0.0°C]; P = 0.009) , PSI (-0.4 [-0.7, -0.1]; P = 0.015) and thigh-predicted sweat [Na + ] (-9 [-13, -5 mmol·L -1 ]; P < 0.001) were observed in IC but not MHA and IT (all P > 0.05). Resting HR (MHA, -4 bpm [-7, 0 bpm]; P = 0.025; IC, -7 bpm [-10, -4 bpm]; P < 0.001; IT, -4 bpm [-8, -1 bpm]; P = 0.008) and mean exercise HR (MHA, -4 [-8, 0 bpm]; P = 0.034; IC, -11 bpm [-15, -8 bpm]; P < 0.001, IT = -5 bpm [-9, -1 bpm]; P = 0.012) were lowered in all groups after training. Isothermic conditioning elicited a greater attenuation in mean exercise HR and thigh-predicted sweat [Na + ] relative to MHA (both P < 0.05). No between-group differences were observed when comparing MHA and IT (all P > 0.05)., Conclusions: Isothermic conditioning induced a more complete heat-adapted phenotype relative to MHA and IT. Interval training may serve as a time efficient alternative to MHA., (Copyright © 2022 by the American College of Sports Medicine.)

Objectives: The ACSM recommends drinking to avoid loss of body mass >2% during exercise to avert compromised performance. Our study aimed to assess the level of dehydration in elite runners following a city marathon in a tropical environment., Design: Prospective cohort design., Methods: Twelve elite runners (6 males, 6 females; age 24-41 y) had body mass measured to the nearest 0.01kg in their race attire immediately before and after the 2017 Standard Chartered Singapore Marathon 2017. Body mass change was corrected for respiratory water loss, gas exchange, and sweat retained in clothing, and expressed as % of pre-race mass (i.e. % dehydration)., Results: Data are expressed as means±SD (range). Dry bulb temperature and humidity were 27.9±0.1°C (27.4-28.3°C) and 79±2% (73-82%). Finish time was 155±10min (143-172min). Male runners finishing positions ranged from 2-12 out of 7627 finishers, whilst female runners placed 1-8 out of 1754 finishers. Body mass change (loss) and % dehydration for all runners were 2.5±0.5kg (1.8-3.5kg) and 4.6±0.9% (3.6-6.8%). Male runners experienced body mass loss of 2.8±0.5kg and 4.9±1.2% while females experienced body mass loss of 2.1±0.2kg and 4.3±0.6%., Conclusions: Despite experiencing dehydration (4.6% body mass loss) two-fold higher than current fluid replacement guidelines recommend (≤2%), elite male and female runners performed successfully and without medical complication in a hot weather marathon., (Copyright © 2021 Sports Medicine Australia. All rights reserved.)

Objectives: We investigated the thermoregulatory responses to ice slurry ingestion during low- and moderate-intensity exercises with restrictive heat loss., Design: Randomised, counterbalanced, cross-over design., Methods: Following a familiarisation trial, ten physically active males exercised on a motorised treadmill at low-intensity (L; 40% VO 2max ) or moderate-intensity (M; 70% VO 2max ) for 75-min, in four randomised, counterbalanced trials. Throughout the exercise bout, participants donned a raincoat to restrict heat loss. Participants ingested 2gkg -1 body mass of ambient water (L+AMB and M+AMB trials) or ice slurry (L+ICE and M+ICE trials) at 15-min intervals during exercise in environmental conditions of T db, 25.1±0.6°C and RH, 63±5%. Heart rate (HR), gastrointestinal temperature (T gi ), mean weighted skin temperature (T sk ), estimated sweat loss, ratings of perceived exertion (RPE) and thermal sensation (RTS) were recorded., Results: Compared to L+AMB, participants completed L+ICE trials with lower ΔT gi (0.8±0.3°C vs 0.6±0.2°C; p=0.03), mean RPE (10±1 vs 9±1; p=0.03) and estimated sweat loss (0.91±0.2L vs 0.78±0.27L; p=0.04). Contrastingly, T gi (p=0.22), T sk (p=0.37), HR (p=0.31), RPE (p=0.38) and sweat loss (p=0.17) were similar between M+AMB and M+ICE trials. RTS was similar during both low-intensity (4.9±0.5 vs 4.7±0.3; p=0.10) and moderate-intensity exercise (5.3±0.47 vs 5.0±0.4; p=0.09)., Conclusions: Per-cooling using ice slurry ingestion marginally reduced thermal strain during low-intensity but not during moderate-intensity exercise. Ice slurry may be an effective and practical heat mitigation strategy during low-intensity exercise such as in occupational and military settings, but a greater volume should be considered to ensure its efficacy., (Copyright © 2020 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

Bcl-2 phosphorylation at serine-70 (S70pBcl2) confers resistance against drug-induced apoptosis. Nevertheless, its specific mechanism in driving drug-resistance remains unclear. We present evidence that S70pBcl2 promotes cancer cell survival by acting as a redox sensor and modulator to prevent oxidative stress-induced DNA damage and execution. Increased S70pBcl2 levels are inversely correlated with DNA damage in chronic lymphocytic leukemia (CLL) and lymphoma patient-derived primary cells as well as in reactive oxygen species (ROS)- or chemotherapeutic drug-treated cell lines. Bioinformatic analyses suggest that S70pBcl2 is associated with lower median overall survival in lymphoma patients. Empirically, sustained expression of the redox-sensitive S70pBcl2 prevents oxidative stress-induced DNA damage and cell death by suppressing mitochondrial ROS production. Using cell lines and lymphoma primary cells, we further demonstrate that S70pBcl2 reduces the interaction of Bcl-2 with the mitochondrial complex-IV subunit-5A, thereby reducing mitochondrial complex-IV activity, respiration and ROS production. Notably, targeting S70pBcl2 with the phosphatase activator, FTY720, is accompanied by an enhanced drug-induced DNA damage and cell death in CLL primary cells. Collectively, we provide a novel facet of the anti-apoptotic Bcl-2 by demonstrating that its phosphorylation at serine-70 functions as a redox sensor to prevent drug-induced oxidative stress-mediated DNA damage and execution with potential therapeutic implications., (© The Author(s) 2020. Published by Oxford University Press on behalf of Nucleic Acids Research.)

As global temperatures continue to rise, improving thermal tolerance in the aged population is crucial to counteract age-associated impairments in thermoregulatory function. Impairments in reflex cutaneous vasodilation and sweating response can augment the vulnerability of older adults to heat-related injuries following exposure to heat stress. Mechanisms underlying a compromised cutaneous vasodilation are suggested to include reduced sympathetic neural drive, diminished cholinergic co-transmitter contribution, and altered second messenger signaling events. On the other hand, impairments in sweating response are ascribed to reduced sweat gland cholinergic sensitivity and altered cyclooxygenase and nitric oxide signaling. Several practical mitigation strategies such as exercise, passive heating, and behavioral adaptations are proposed as means to overcome heat stress and improve thermal tolerance in the aged. Aerobic exercise training is shown to be amongst the most effective ways to enhance thermoregulatory function. However, in elderly with limited exercise capability due to chronic diseases and mobility issues, passive heating can serve as a functional alternative as it has been shown to confer similar benefits to that of exercise training. Supplementary to exercise training and passive heating, behavioral adaptations can be applied to further enhance the heat-preparedness of the aged., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Background: Wrist-worn activity trackers are popular, and an increasing number of these devices are equipped with heart rate (HR) measurement capabilities. However, the validity of HR data obtained from such trackers has not been thoroughly assessed outside the laboratory setting., Objective: This study aimed to investigate the validity of HR measures of a high-cost consumer-based tracker (Polar A370) and a low-cost tracker (Tempo HR) in the laboratory and free-living settings., Methods: Participants underwent a laboratory-based cycling protocol while wearing the two trackers and the chest-strapped Polar H10, which acted as criterion. Participants also wore the devices throughout the waking hours of the following day during which they were required to conduct at least one 10-min bout of moderate-to-vigorous physical activity (MVPA) to ensure variability in the HR signal. We extracted 10-second values from all devices and time-matched HR data from the trackers with those from the Polar H10. We calculated intraclass correlation coefficients (ICCs), mean absolute errors, and mean absolute percentage errors (MAPEs) between the criterion and the trackers. We constructed decile plots that compared HR data from Tempo HR and Polar A370 with criterion measures across intensity deciles. We investigated how many HR data points within the MVPA zone (≥64% of maximum HR) were detected by the trackers., Results: Of the 57 people screened, 55 joined the study (mean age 30.5 [SD 9.8] years). Tempo HR showed moderate agreement and large errors (laboratory: ICC 0.51 and MAPE 13.00%; free-living: ICC 0.71 and MAPE 10.20%). Polar A370 showed moderate-to-strong agreement and small errors (laboratory: ICC 0.73 and MAPE 6.40%; free-living: ICC 0.83 and MAPE 7.10%). Decile plots indicated increasing differences between Tempo HR and the criterion as HRs increased. Such trend was less pronounced when considering the Polar A370 HR data. Tempo HR identified 62.13% (1872/3013) and 54.27% (5717/10,535) of all MVPA time points in the laboratory phase and free-living phase, respectively. Polar A370 detected 81.09% (2273/2803) and 83.55% (9323/11,158) of all MVPA time points in the laboratory phase and free-living phase, respectively., Conclusions: HR data from the examined wrist-worn trackers were reasonably accurate in both the settings, with the Polar A370 showing stronger agreement with the Polar H10 and smaller errors. Inaccuracies increased with increasing HRs; this was pronounced for Tempo HR., (©Andre Matthias Matthias Müller, Nan Xin Wang, Jiali Yao, Chuen Seng Tan, Ivan Cherh Chiet Low, Nicole Lim, Jeremy Tan, Agnes Tan, Falk Müller-Riemenschneider. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 02.10.2019.)

Hypohydration exceeding 2% body mass can impair endurance capacity. It is postulated that the brain could be perturbed by hypohydration, leading to impaired motor performance. We investigated the neural effects of hypohydration with magnetic resonance imaging (MRI). Ten men were dehydrated to approximately -3% body mass by running on a treadmill at 65% maximal oxygen consumption (V̇o 2max ) before drinking to replace either 100% [euhydration (EU)] or 0% [hypohydration (HH)] of fluid losses. MRI was performed before start of trial (baseline) and after rehydration phase (post) to evaluate brain structure, cerebral perfusion, and functional activity. Endurance capacity assessed with a time-to-exhaustion run at 75% V̇o 2max was reduced with hypohydration (EU: 45.2 ± 9.3 min, HH: 38.4 ± 10.7 min; P = 0.033). Mean heart rates were comparable between trials (EU: 162 ± 5 beats/min, HH: 162 ± 4 beats/min; P = 0.605), but the rate of rise in rectal temperature was higher in HH trials (EU: 0.06 ± 0.01°C/min, HH: 0.07 ± 0.02°C/min; P < 0.01). In HH trials, a reduction in total brain volume (EU: +0.7 ± 0.6%, HH: -0.7 ± 0.9%) with expansion of ventricles (EU: -2.7 ± 1.6%, HH: +3.7 ± 3.3%) was observed, and vice versa in EU trials. Global and regional cerebral perfusion remained unchanged between conditions. Functional activation in the primary motor cortex in left hemisphere during a plantar-flexion task was similar between conditions (EU: +0.10 ± 1.30%, HH: -0.11 ± 0.31%; P = 0.637). Our findings demonstrate that with exertional hypohydration, brain volumes were altered but the motor-related functional activity was unperturbed. NEW & NOTEWORTHY Dehydration occurs rapidly during prolonged or intensive physical activity, leading to hypohydration if fluid replenishment is insufficient to replace sweat losses. Altered hydration status poses an osmotic challenge for the brain, leading to transient fluctuations in brain tissue and ventricle volumes. Therefore, the amount of fluid ingestion during exercise plays a critical role in preserving the integrity of brain architecture. These structural changes, however, did not translate directly to motor functional deficits in a simple motor task.

The central nervous system, specifically the brain, is implicated in the development of exertional fatigue under a hot environment. Diverse neuroimaging techniques have been used to visualize the brain activity during or after exercise. Notably, the use of magnetic resonance imaging (MRI) has become prevalent due to its excellent spatial resolution and versatility. This review evaluates the significance and limitations of various brain MRI techniques in exercise studies-brain volumetric analysis, functional MRI, functional connectivity MRI, and arterial spin labeling. The review aims to provide a summary on the neural basis of exertional fatigue and proposes future directions for brain MRI studies. A systematic literature search was performed where a total of thirty-seven brain MRI studies associated with exercise, fatigue, or related physiological factors were reviewed. The findings suggest that with moderate dehydration, there is a decrease in total brain volume accompanied with expansion of ventricular volume. With exercise fatigue, there is increased activation of sensorimotor and cognitive brain areas, increased thalamo-insular activation and decreased interhemispheric connectivity in motor cortex. Under passive hyperthermia, there are regional changes in cerebral perfusion, a reduction in local connectivity in functional brain networks and an impairment to executive function. Current literature suggests that the brain structure and function are influenced by exercise, fatigue, and related physiological perturbations. However, there is still a dearth of knowledge and it is hoped that through understanding of MRI advantages and limitations, future studies will shed light on the central origin of exertional fatigue in the heat., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)