Passive heat interventions (PHIs) are non-exercise heat-acclimation strategies that improve physiological markers associated with heat tolerance and reduce vulnerability to heat-related illness, when exercise is not feasible. However, representation of female participants within this literature remains unclear. In this study, we integrated an audit of PHI research with a systematic review of selected heat-adaptation phenotypes to characterize current practices and identify methodological gaps. Using a standardized framework, searches of PubMed, Web of Science, ScienceDirect, SPORT Discus and Scopus were conducted. Included studies implemented PHIs (≥3 days) and reported markers of heat adaptation. Seventy-three studies (1392 participants; 427 females) met inclusion criteria. Six studies recruited only female participants, four conducted sex-based subanalyses, and none was designed to examine sex differences. No study achieved gold classification menstrual status reporting, with most classified as ungraded (n = 16) or unclassified (n = 22), using the standardized framework. Participants were predominantly sedentary, recreationally active or trained, with ∼49% representing clinical populations. The systematic review showed PHI-associated heat-adaptation outcomes, including changes in core temperature (0.0°C to -0.5°C), skin temperature (-0.4°C to 0.1°C), heart rate (-2 to -11 beats min-1), blood pressure (-2 to -5 mmHg), plasma volume (-1% to 22%) and sweat rate (0.1 to 0.4 L h-1). PHI research is characterized by female underrepresentation and limited menstrual status reporting, constraining confidence in how evidence reflects the broader population. Although PHIs can modify the heat-adaptation phenotype, these responses are derived largely from male participants. Sex-informed trials are needed to strengthen mechanistic understanding and translational application.

Climate change has resulted in an increase in heat exposure globally. There is strong evidence that this increased heat stress is associated with poor maternal and fetal outcomes, especially in vulnerable populations. However, there remains poor understanding of the biological pathways and mechanisms involved in the impact of heat in pregnancy. This observational cohort study of 764 pregnant participants based in sub-Saharan Africa, a geographical region at risk of extreme heat events, aims to evaluate the physiological and biochemical changes that occur in pregnancy due to heat stress. The key objectives of the study are to 1) map exposure to heat stress in the cohort and understand what environmental, social and community factors increase the risk of extreme heat exposure; 2) assess the impact of heat stress on maternal health, e.g. heat strain, subjective psychological well-being, sleep and activity level; 3) evaluate how heat stress impacts placenta structure and function; 4) determine how chronic heat exposure impacts birth outcomes; and 5) explore the epigenetic changes in the placenta and infant by heat stress exposure per trimester. Pregnant women will be recruited from two distinct regions in The Gambia to exploit the naturally occurring heat gradient across the country. Microclimate mapping of the area of recruitment will give detailed exposure measurements. Participants will be asked to wear a watch-style device at 28- and 35-weeks gestational age to evaluate maternal heart rate, activity and sleep. At the end of the week, an ultrasound scan will be performed to evaluate fetal size and placental blood flow. At delivery, birth outcomes will be recorded and maternal, placental and cord samples taken for epigenetic, biochemical and histological evaluation. Evaluation of neuro-behaviour and final infant samples will be taken at 1 month following birth.

Sleep hygiene can be defined as practicing habits that facilitate sleep; poor sleep hygiene is common among elite athletes, and improving this can be one way to enhance sleep indices. Given the large inter-individual variability of sleep, there is a need for further investigation into individualised sleep hygiene for elite female athletes, with consideration for the practical application of the method. Using a self-controlled time series design with repeated measures, n = 16 professional female footballers completed a 9-week study during mid-season. Monitoring of sleep (actigraphy, self-report) occurred at week 1, 4, 7 and 9-a control period occurred at week 2 and 3, and a subsequent intervention period occurred at weeks 5 and 6. Based on baseline sleep monitoring, media-based messages were designed with the purpose of giving a singular sleep hygiene message; all participants received these individualised messages daily across the 2-week intervention period at a standardised time of 8.00 p.m., with the intention of them actioning the sleep hygiene point. One-way analysis of variance with repeated measures was conducted to assess the differences between control period, intervention period and follow-up for each measured variable. Significant differences were observed post-intervention for sleep efficiency (p < 0.001) and sleep latency (p < 0.001), whereas the athlete sleep behaviour questionnaire score significantly improved in the follow-up period (week 9) post intervention (p = 0.039). This is the first study to present this novel method of individualised sleep hygiene education for elite female athletes and is also the first study to demonstrate the use of sleep hygiene interventions to improve sleep factors for female athletes' mid-season. This demonstrates a promising, time-efficient approach to sleep hygiene education, with a potentially wide scope of application, as well as demonstrating there is indeed potential for elite female athletes to gain sleep improvements mid-season.

Climate change has resulted in an increase in heat exposure globally. There is strong evidence that this increased heat stress is associated with poor maternal and fetal outcomes, especially in vulnerable populations. However, there remains poor understanding of the biological pathways and mechanisms involved in the impact of heat in pregnancy. This observational cohort study of 764 pregnant participants based in sub-Saharan Africa, a geographical region at risk of extreme heat events, aims to evaluate the physiological and biochemical changes that occur in pregnancy due to heat stress. The key objectives of the study are to 1) map exposure to heat stress in the cohort and understand what environmental, social and community factors increase the risk of extreme heat exposure; 2) assess the impact of heat stress on maternal health, e.g. heat strain, subjective psychological well-being, sleep and activity level; 3) evaluate how heat stress impacts placenta structure and function; 4) determine how chronic heat exposure impacts birth outcomes; and 5) explore the epigenetic changes in the placenta and infant by heat stress exposure per trimester. Pregnant women will be recruited from two distinct regions in The Gambia to exploit the naturally occurring heat gradient across the country. Microclimate mapping of the area of recruitment will give detailed exposure measurements. Participants will be asked to wear a watch-style device at 28- and 35-weeks gestational age to evaluate maternal heart rate, activity and sleep. At the end of the week, an ultrasound scan will be performed to evaluate fetal size and placental blood flow. At delivery, birth outcomes will be recorded and maternal, placental and cord samples taken for epigenetic, biochemical and histological evaluation. Evaluation of neuro-behaviour and final infant samples will be taken at 1 month following birth.

Abstract Background Sleep is often compromised in athletes. The monitoring of athlete’s sleep is an important preventative and educational tool. With many athletes using daily questionnaires to estimate sleep quality, there is a need to understand what this term is indicating when self-reported, and thus whether a self-report of this factor is useful. Aims This study aimed to compare self-reported and actigraph reported sleep quality, with a view to further understanding the constructs of this parameter. Methods Twenty-two national level female footballers provided a daily self-report of sleep quality (Likert scale) across 7 days, whilst also wearing an actigraph across the same testing period. Linear regression analysis was carried out to see which actigraph derived factors contributed to self-report score. Results The incorporation of SE, number of wakings and SFI could only account for 27.5% of variance in self-reported sleep quality scores. Number of wakings was the only significant predictor for self-reported sleep quality score (p = 0.000). Conclusions When asking for self-report of sleep quality, coaches should infer that number of wakings may be predicting for the Likert score given. Further discussion around this is advised, given the multifactorial nature of sleep quality and the potential for many contributing factors to affect scoring.

Cross -adaptation (CA) refers to the successful induction of physiological adaptation under one environmental stressor (e.g., heat), to enable subsequent benefit in another (e.g., hypoxia). This systematic review and exploratory meta -analysis investigated the effect of heat acclimation (HA) on physiological, perceptual and physical performance outcome measures during rest, and submaximal and maximal intensity exercise in hypoxia. Database searches in Scopus and MEDLINE were performed. Studies were included when they met the Population, Intervention, Comparison, and Outcome criteria, were of English -language, peer-reviewed, full -text original articles, using human participants. Risk of bias and study quality were assessed using the COnsensus based Standards for the selection of health status Measurement INstruments checklist. Nine studies were included, totalling 79 participants (100 % recreationally trained males). The most common method of HA included fixed-intensity exercise comprising 9 +/- 3 sessions, 89 +/- 24 -min in duration and occurred within 39 +/- 2 degrees C and 32 +/- 13 % relative humidity. CA induced a moderate, beneficial effect on physiological measures at rest (oxygen saturation: g = 0.60) and during submaximal exercise (heart rate: g = -0.65, core temperature: g = -0.68 and skin temperature: g = -0.72). A small effect was found for ventilation (g = 0.24) and performance measures (peak power: g = 0.32 and time trial time: g = -0.43) during maximal intensity exercise. No effect was observed for perceptual outcome measures. CA may be appropriate for individuals, such as occupational or military workers, whose access to altitude exposure prior to undertaking submaximal activity in hypoxic conditions is restricted. Methodological variances exist within the current literature, and females and well-trained individuals have yet to be investigated. Future research should focus on these cohorts and explore the mechanistic underpinnings of CA.

Sleep is often compromised in female athletes, and the monitoring of female athletes' sleep is an important preventative and educational tool. With self-reporting of sleep common practice for athletes as part of a daily wellness assessment, there is a need to understand whether sleep indices are being reported accurately, and thus whether self-report data are useful. This study aimed to compare the agreement between self-reported and actigraphy reported sleep duration in female football players, with the intention of informing best practice for athlete monitoring. Twenty-two female footballers (mean age 19.5 +/- 1.3 years) provided a daily self-report across 7 days, whilst also wearing an actigraph across the same testing period. Agreement between the two measures was assessed using Bland-Altman limits of agreement, with acceptable limits of agreement defined as <30 minutes. Results showed evident disagreement between the two methods, with a mean bias of -0.54 (32 min, 95% CI -0.66 to -0.43) and a potential disagreement range of over 2 h (Lower 95% limits of agreement -1.49 to upper 95% limits of agreement 0.40). Coaches using self-reported sleep durations as a monitoring tool for female footballers should interpret the results with caution and be aware of the potential for inaccuracies in this measure. As such, where possible, coaches should consider other methods of sleep monitoring, rather than solely relying on a self-report, to ensure they are operating with optimal practice within situational constraints.

This study investigated the reliability of the Affinity Altitude hypoxic generator within-day, between-day and between-generator under acute and chronic hypoxic conditions. An additional objective was to assess the validity of the fraction of inspired oxygen (FiO2) values in relation to the claimed manufacture’s reference values to ensure the accuracy and safety of the product. Three altitude generators (Affinity Altitude Ltd., Sussex, UK) were assessed across all available settings during a test–retest design for equivalent FiO2 and output volume. This consisted of two phases: 1) acute exposure (10 min per setting) and 2) chronic exposure (8 h per setting). FiO2 and volume data were calculated from 1 min collection samples using the Douglas bag method for acute and chronic exposures. There were low variations in FiO2 data across all settings within the acute exposure for within-day (coefficient of variation [CV] range: 0.0–2.6

Improved sleep can enhance sprint, endurance, and sports-specific skills; however, it is yet to be investigated whether improved sleep indices could enhance strength and power performance. Sleep hygiene (SH) is growing in popularity as a tool to enhance sleep indices amongst athletic cohorts, yet the optimal delivery strategy of sleep hygiene education is yet to be determined. Using a randomised, controlled design with repeated measures, this study recruited 34 female footballers playing in WSL or WSL academy league. Participants were split into 3 groups: one receiving both group-based and individualised sleep hygiene education, one receiving only group-based SH education and a control group receiving no education. Monitoring of sleep (actigraphy, diaries) and physical performance (countermovement jump, isometric mid-thigh pull) was carried out at week 1, week 4 and week 7. Split-plot ANOVAs were used to assess for differences between groups × weeks, and groups × time. Individualised sleep hygiene education resulted in significantly improved sleep duration (p = 0.005), latency (p = 0.006) and efficiency (p = 0.004) at week 7 compared to controls, whilst also resulting in significantly improved countermovement jump scores (p = 0.001) compared to control. Results of this study suggest that jump performance may be affected by sleep factors, and that individualised SH may be superior to group-based SH, providing information to coaches regarding training optimisation and the efficacy of SH education methods.

Studies on the effect of heat stress on pregnant women are scarce, particularly in highly vulnerable populations. To support the risk assessment of pregnant subsistence farmers in the West Kiang district, The Gambia we conducted a study on the pathophysiological effects of extreme heat stress and assessed the applicability of heat stress indices. From ERA5 climate reanalysis we added location-specific modelled solar radiation to datasets of a previous observational cohort study involving on-site measurements of 92 women working in the heat. Associations between physiological and environmental variables were assessed through Pearson correlation coefficient analysis, mixed effect linear models with random intercepts per participant and confirmatory composite analysis. We found Pearson correlations between r-values of 0 and 0.54, as well as independent effects of environmental variables on skin- and tympanic temperature, but not on heart rate, within a confidence interval of 98%. Pregnant women experienced stronger pathophysiological effects from heat stress in their third rather than in their second trimester. Environmental heat stress significantly altered maternal heat strain, particularly under humid conditions above a 50% relative humidity threshold, demonstrating interactive effects. Based on our results, we recommend including heat stress indices (e.g. UTCI or WBGT) in local heat-health warning systems.

Introduction: Passive heating is receiving increasing attention within human performance and health contexts. A low-cost, portable steam sauna pod may offer an additional tool for those seeking to manipulate physiological (cardiovascular, thermoregulatory and sudomotor) and perceptual responses for improving sporting or health profiles. This study aimed to 1) report the different levels of heat stress and determine the pods' inter-unit reliability, and 2) quantify the reliability of physiological and perceptual responses to passive heating. Method: In part 1, five pods were assessed for temperature and relative humidity (RH) every 5 min across 70 min of heating for each of the 9 settings. In part 2, twelve males (age: 24 +/- 4 years) completed two 60 min trials of passive heating (3 x 20 min at 44 degrees C/99% RH, separated by 1 week). Heart rate (HR), rectal (T-rectal) and tympanic temperature (T-tympanic) were recorded every 5 min, thermal comfort (T-comfort) and sensation (T-sensation) every 10 min, mean arterial pressure (MAP) at each break period and sweat rate (SR) after exiting the pod. Results: In part 1, setting 9 provided the highest temperature (44.3 +/- 0.2 degrees C) and longest time RH remained stable at 99% (51 +/- 7 min). Inter-unit reliability data demonstrated agreement between pods for settings 5-9 (intra-class correlation [ICC] >0.9), but not for settings 1-4 (ICC <0.9). In part 2, between-visits, high correlations, and low typical error of measurement (TEM) and coefficient of variation (CV) were found for T-rectal, HR, MAP, SR, and T-comfort, but not for T-tympanic or T-sensation. A peak T-rectal of 38.09 +/- 0.30 degrees C, HR of 124 +/- 15 b min(-1) and a sweat loss of 0.73 +/- 0.33 L were reported. No between-visit differences (p > 0.05) were observed for T-rectal, T-tympanic, T-sensation or T-comfort, however HR (+3 b.min(-1)) and MAP (+4 mmHg) were greater in visit 1 vs. 2 (p < 0.05). Conclusion: Portable steam sauna pods generate reliable heat stress between-units. The highest setting (44 degrees C/99% RH) also provides reliable but modest adjustments in physiological and perceptual responses.

Tests of human endeavour have assessed exercise performance since the Ancient Greeks who visually inspected their Spartan athletes. Hot environments exacerbate the physiological demands of exercise, often leading to performance impairments and/or a risk of heat-related illness (HRI). Heat tolerance represents an individual's ability to mitigate or avoid extreme body temperature elevations when exercising in hot environments. Heat tolerance tests have evaluated military personnel that have previously experienced an HRI. The choice of exercise performance tests within heat stress is comparable to those undertaken in temperate conditions, albeit requiring additional safety monitoring and data interpretation considerations. Practitioners are encouraged to match heat stress conditions of the expected environment and the sport demands during testing for accurate performance interpretation. Education also facilitates the athlete's ownership and 'buy-in' for implementing testing. Consideration of scientific principles of all measures is necessary for accurate data interpretation during single or repeated heat stress testing.

Objective To evaluate the impact of heat stress on umbilical artery resistance index (RI) measured by UmbiFlow™ in field settings and the implications for pregnancy outcomes.Methods This feasibility study was conducted in West Kiang, The Gambia, West Africa; a rural area with increasing exposure to extreme heat. We recruited women with singleton fetuses who performed manual tasks (such as farming) during pregnancy. The umbilical artery RI was measured at rest, during and at the end of a typical working shift in women ≥ 28 weeks’ gestation. Adverse pregnancy outcomes (APO) were classified as stillbirth, preterm birth, low birth weight, or small for gestational age, and all other outcomes as normal.Results A total of 40 participants were included; 23 normal births and 17 APO. Umbilical artery RI demonstrated a nonlinear relationship to heat stress, with indication of a potential threshold value for placental insufficiency around 32ºC by universal thermal climate index. Preliminary evidence suggests the fetoplacental circulation response to heat stress differs in APO versus normal outcome.Conclusions The Umbiflow™ device proved to be an effective field method for assessing placental function. Dynamic changes in RI may begin to explain the association between extreme heat and APO.Funding The Wellcome Trust (216336/Z/19/Z)Synopsis Extreme heat exposure is increasing and a low-cost umbilical artery doppler device, UmbiFlow™, can aid understanding of fetoplacental function under heat stress conditions.### Competing Interest StatementThe authors have declared no competing interest.### Funding StatementThis project was funded by the Wellcome Trust through the Wellcome Trust Global Health PhD Fellowship awarded to AB (216336/Z/19/Z). The funders had no role in study design, data collection, analysis, manuscript writing or decision to submit.### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:The study was approved by the Gambia government/MRC Joint ethics committee and the London School of Hygiene and Tropical Medicine Ethics Advisory Board (ref: 16405) in accordance with the Declaration of Helsinki (2013).I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesAnonymised data will be made available on reasonable request from the corresponding author.

Background Anthropogenic climate change has caused extreme temperatures worldwide, with data showing that sub-Saharan Africa is especially vulnerable to these changes. In sub-Saharan Africa, women comprise 50% of the agricultural workforce, often working throughout pregnancy despite heat exposure increasing the risk of adverse birth outcomes. In this study, we aimed to improve understanding of the pathophysiological mechanisms responsible for the adverse health outcomes resulting from environmental heat stress in pregnant subsistence farmers. We also aimed to provide data to establish whether environmental heat stress also has physiological effects on the fetus.Methods We conducted an observational cohort study in West Kiang, The Gambia, at the field station for the Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine (named the MRC Keneba field station). Pregnant women who were aged 16 years or older and who were at < 36 weeks' gestation of any gravida or parity were invited to participate in the study. Participants were eligible if they were involved in agricultural or related manual daily tasks of living. Participants were ineligible if they refused to provide consent, had multiple pregnancies (eg, if they had twins), were acutely unwell, or were diagnosed with pre-eclampsia or eclampsia. Heat stress was measured by wet bulb globe temperature (WBGT) and by using the universal thermal climate index (UTCI), and maternal heat strain was directly measured by modified physiological strain index calculated from heart rate and skin temperature. Outcome measures of fetal heart rate (FHR) and fetal strain (defined as a FHR > 160 beats per min [bpm] or < 115 bpm, or increase in umbilical artery resistance index) were measured at rest and during the working period. Multivariable repeated measure models (linear regression for FHR, and logistic regression for fetal strain) were used to evaluate the association of heat stress and heat strain with acute fetal strain.Findings Between Aug 26, 2019, and March 27, 2020, 92 eligible participants were recruited to the study. Extreme heat exposure was frequent, with average exposures of WBGT of 27middot2 degrees C (SD 3middot6 degrees C) and UTCI equivalent temperature of 34middot0 degrees C (SD 3middot7 degrees C). The total effect of UTCI on fetal strain resulted in an odds ratio (OR) of 1middot17 (95% CI 1middot09-1middot29; p < 0middot0001), with an adjusted direct effect of OR of 1middot12 (1middot03-1middot21; p=0middot010) with each 1 degrees C increase in UTCI. The adjusted OR of maternal heat strain on fetal strain was 1middot20 (1middot01-1middot43; p=0middot038), using the UTCI model, with each unit increase. Interpretation Data from our study show that decreasing maternal exposure to heat stress and heat strain is likely to reduce fetal strain, with the potential to reduce adverse birth outcomes. Further work that explores the association between heat stress and pregnancy outcomes in a variety of settings and populations is urgently needed to develop effective interventions.

Purpose Elite endurance runners frequently utilise live high-train high (LHTH) altitude training to improve endurance performance at sea level (SL). Individual variability in response to the hypoxic exposure have resulted in contradictory findings. In the present case study, changes in total haemoglobin mass (tHbmass) and physiological capacity, in response to 4-weeks of LHTH were documented. We tested if a hypoxic sensitivity test (HST) could predict altitude-induced adaptations to LHTH. Methods Fifteen elite athletes were selected to complete 4-weeks of LHTH (~ 2400 m). Athletes visited the laboratory for preliminary testing (PRE), to determine lactate threshold (LT), lactate turn point (LTP), maximal oxygen uptake VO 2max and tHbmass. During LHTH, athletes completed daily physiological measures [arterial oxygen saturation (SpO 2 ) and body mass] and subjective wellbeing questions. Testing was repeated, for those who completed the full camp, post-LHTH (POST). Additionally, athletes completed the HST prior to LHTH. Results A difference ( P < 0.05) was found from PRE to POST in average tHbmass (1.8% ± 3.4%), VO 2max (2.7% ± 3.4%), LT (6.1% ± 4.6%) and LTP (5.4% ± 3.8%), after 4-weeks LHTH. HST revealed a decrease in oxygen saturation at rest (ΔSp r ) and higher hypoxic ventilatory response at rest (HVR r ) predicted individual changes tHbmass. Lower hypoxic cardiac response at rest (HCR r ) and higher HVR r predicted individual changes VO 2max . Conclusion Four weeks of LHTH at ~ 2400 m increased tHbmass and enhanced physiological capacity in elite endurance runners. There was no observed relationship between these changes and baseline characteristics, pre-LHTH serum ferritin levels, or reported incidents of musculoskeletal injury or illness. The HST did however, estimate changes in tHbmass and VO 2max . HST prior to LHTH could allow coaches and practitioners to better inform the acclimatisation strategies and training load application of endurance runners at altitude.

OBJECTIVE:To evaluate the use of UmbiFlow™ in field settings to assess the impact of heat stress on umbilical artery resistance index (RI). METHODS:This feasibility study was conducted in West Kiang, The Gambia, West Africa; a rural area with increasing exposure to extreme heat. We recruited women with singleton fetuses who performed manual tasks (such as farming) during pregnancy to an observational cohort study. The umbilical artery RI was measured at rest, and during and at the end of a typical working shift in women at 28 weeks or more of pregnancy. Adverse pregnancy outcomes (APO) were classified as stillbirth, preterm birth, low birth weight, or small for gestational age, and all other outcomes as normal. RESULTS:A total of 40 participants were included; 23 normal births and 17 APO. Umbilical artery RI demonstrated a nonlinear relationship to heat stress, with indication of a potential threshold value for placental insufficiency at 32°C by universal thermal climate index and 30°C by wet bulb globe temperature. CONCLUSIONS:The Umbiflow device proved to be an effective field method for assessing placental function. Dynamic changes in RI may begin to explain the association between extreme heat and APO with an identified threshold of effect.

Objectives: To investigate the efficacy of heat acclimation (HA) in the young (Y-EX) and elderly (E-EX) following exercise-HA, and the elderly utilising post-exercise hot water immersion HA (E-HWI). Design: Cross-sectional study. Method: Twenty-six participants (Y-EX: n = 11 aged 22 +/- 2 years, E-EX: n = 8 aged 68 +/- 3 years, E-HWI: n = 7 aged 73 +/- 3 years) completed two pre-/post-tests, separated by five intervention days. Y-EX and E-EX exercised in hot conditions to raise rectal temperature (T-rec) >= 38.5 degrees C within 60 min, with this increase maintained for a further 60 min. E-HWI completed 30 min of cycling in temperate conditions, then 30 min of HWI (40 degrees C), followed by 30 min seated blanket wrap. Pre-and post-testing comprised 30 min rest, followed by 30 min of cycling exercise (3.5 W.kg(-1) H-prod), and a six-minute walk test (6MWT), all in 35 degrees C, 50% RH. Results: The HA protocols did not elicit different mean heart rate (HR), T-rec, and duration T-rec >= 38.5 degrees C (p > 0.05) between Y-EX, E-EX, and E-HWI groups. Resting T-rec, peak skin temperature, systolic and mean arterial pressure, perceived exertion and thermal sensation decreased, and 6MWT distance increased pre-to post-HA (p < 0.05), with no difference between groups. Y-EX also demonstrated a reduction in resting HR (p < 0.05). No change was observed in peak T-rec or HR, vascular conductance, sweat rate, or thermal comfort in any group (p > 0.05). Conclusions: Irrespective of age or intervention, HA induced thermoregulatory, perceptual and exercise performance improvements. Both exercise-HA (E-EX), and post-exercise HWI (E-HWI) are considered viable interventions to prepare the elderly for heat stress. (C) 2021 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Background: Personal protective equipment (PPE) is an essential component of safely treating suspected or confirmed SARS-CoV-2 patients. PPE acts as a barrier to heat loss, therefore increasing the risk of thermal strain which may impact on cognitive function. Healthcare workers (HCWs) need to be able to prioritize and execute complex tasks effectively to ensure patient safety. This study evaluated pre-cooling and per-cooling methods on thermal strain, thermal comfort and cognitive function during simulated emergency management of an acutely unwell patient. Methods: This randomized controlled crossover trial was run at the Clinical Services Department of the Medical Research Unit The Gambia. Each participant attended two sessions (Cool and Control) in standard PPE. Cool involved pre-cooling with an ice slurry ingestion and per-cooling by wearing an ice-vest external to PPE. Results: Twelve participants completed both sessions. There was a significant increase in tympanic temperature in Control sessions at both 1 and 2 h in PPE (p = 0.01). No significant increase was seen during Cool. Effect estimate of Cool was −0.2°C (95% CI −0.43; 0.01, p = 0.06) post 1 h and −0.28°C (95% CI −0.57; 0.02, p = 0.06) post 2 h on tympanic temperature. Cool improved thermal comfort (p < 0.001), thermal sensation (p < 0.001), and thirst (p = 0.04). No difference on cognitive function was demonstrated using multilevel modeling. Discussion: Thermal strain in HCWs wearing PPE can be safely reduced using pre- and per-cooling methods external to PPE.

This study aimed to assess how female breast cancer survivors (BCS) respond physiologically, hematologically, and perceptually to exercise under heat stress compared to females with no history of breast cancer (CON). Twenty-one females (9 BCS and 12 CON [age; 54 +/- 7 years, stature; 167 +/- 6 cm, body mass; 68.1 +/- 7.62 kg, and body fat; 30.9 +/- 3.8%]) completed a warm (25 degrees C, 50% relative humidity, RH) and hot (35 degrees C, 50%RH) trial in a repeated-measures crossover design. Trials consisted of 30 min of rest, 30 min of walking at 4 metabolic equivalents, and a 6-minute walk test (6MWT). Physiological measurements (core temperature (T-re), skin temperature (T-skin), heart rate (HR), and sweat analysis) and perceptual rating scales (ratings of perceived exertion, thermal sensation [whole body and localized], and thermal comfort) were taken at 5- and 10-min intervals throughout, respectively. Venous blood samples were taken before and after to assess; IL-6, IL-10, CRP, IFN-gamma, and TGF-beta(1). All physiological markers were higher during the 35 versus 25 degrees C trial; T-re (similar to 0.25 degrees C, p = 0.002), T-skin (similar to 3.8 degrees C, p < 0.001), HR (similar to 12 beats.min(-1), p = 0.023), and whole-body sweat rate (similar to 0.4 L.hr(-1), p < 0.001), with no difference observed between groups in either condition (p > 0.05). Both groups covered a greater 6MWT distance in 25 versus 35 degrees C (by similar to 200 m; p = 0.003). Nevertheless, the control group covered more distance than BCS, regardless of environmental temperature (by similar to 400 m, p = 0.03). Thermoregulation was not disadvantaged in BCS compared to controls during moderate-intensity exercise under heat stress. However, self-paced exercise performance was reduced for BCS regardless of environmental temperature.