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Abstract: Introduction: Tumor necrosis factor-α (TNFα) is a major mediator of insulin resistance. On the other hand, it has been suggested that TNFα may facilitate glucose uptake through GLUT 1 expression. We recently found that physical exercise prevented the progression to type 2 diabetes mellitus in diabetes prone Psammomys obesus (sand rat). Aim: The aim of the present study was to characterize the influence of physical exercise on the expression of TNFα, its receptor R1 and GLUT 1 in muscle tissue of this animal model. Methods: Animals were assigned for 4 weeks to four groups: high-energy diet (HC), high-energy diet and exercise (HE), low-energy diet (LC), low-energy diet and exercise (LE). TNFα, R1 and GLUT 1 expression were analyzed using Western blot technique. Results: None of the animals in the HE group became diabetic while all the animals in the HC group became diabetic. TNFα, its receptor (R1) and GLUT 1 expressions were significantly higher in the two exercising groups (LE and HE) and significantly lower in the HC group compared to the control LC group. Conclusions: Physical exercise augments the expression of TNFα, its receptor R1 and the glucose transporter GLUT 1 in muscle tissue. We suggest that this mechanism may improve glucose uptake through pathways parallel and unrelated to insulin signaling that may include MAPK and/or NO. These biochemical processes contribute to the beneficial effects of physical exercise on the prevention of type 2 diabetes mellitus. [Copyright &y& Elsevier]

A simple mathematical model was developed to grade the results of the fraction of inspiratory CO2 levels in respiratory protective devices (RPDs). Using this model, the level of FiCO2 of two chemical warfare RPDs was monitored during the examination of 54 young male volunteers at rest and exercise. No set of results distributed in a normal Gaussian mode; therefore, parametric statistics could not be used to analyze the group's results. Yet the model allowed simple and insightful evaluation of the results, stressing differences between the similar RPDs. We suggest continued use of the analysis model as a tool for quantitative evaluation of results and further understanding of the respiratory patterns of RPDs. [ABSTRACT FROM AUTHOR]

Exertional heatstroke is a life-threatening event. It occurs mainly among the young healthy populations of athletes and soldiers. The severity of exertional heatstroke is directly correlated to the area under the temperature duration curve. Therefore, rapid cooling in the field has an enormous effect on prognosis. Four cases of exertional heatstroke are presented which differ in their outcome. We argue that there is a "window time period" within which simple and effective cooling techniques can determine prognosis. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the significance of body surface area-to-mass ratio (BSA/mass) on the heat-tolerance test (HTT) results. We hypothesized that individuals defined as heat tolerant (HT) would have on average higher BSA/mass compared with heat intolerant (HI) individuals., Methods: A retrospective reanalysis of the HTT results of 517 soldiers (age, 18-38 yr; M/F, 96%:4%), who were tested by the Israel Defense Forces HTT protocol. The criterion for heat tolerance in the current analysis was a rectal temperature (T re ) plateau during the second hour of the test. A logistic regression analysis to evaluate the predictive power of BSA/mass for heat intolerance was performed; the spline model was applied to show the odds for heat intolerance across BSA/mass., Results: In men BSA/mass of HI individuals was lower than HT individuals (248 ± 19 vs 262 ± 18 cm 2 ·kg -1 , P < 0.01, d = 0.76). In women a similar trend was noted but with no statistical significance between HT and HI groups. The odd ratio for heat intolerance for every unit increase in BSA/mass was 0.97 (95% confidence interval, 0.95-0.99). The spline model plateaued above BSA/mass of 270 cm 2 ·kg -1 ., Conclusions: The results imply that body-core temperature responses to a standard exercise-heat stress (fixed external work rate and climatic conditions) are influenced by BSA/mass. More specifically, lack of a steady state in T re (indicating heat intolerance) was more likely to occur with every unit decrease in BSA/mass. These findings contribute to a better understanding of the role of body anthropometry in the response to a standard exercise-heat task that might have an implication on clinical decision making about return to duty/play of soldiers, athletes, and others who deemed to be identified as HI., (Copyright © 2024 by the American College of Sports Medicine.)

Background: The prevalence of vitamin D deficiency has been a growing concern in recent years. Vitamin D is important in many of the body's physiological systems, such as the musculoskeletal, cardiovascular and immune functions. A deficiency of vitamin D in athletes may negatively impact both muscle functions and recovery and, thus, affect performance and increase the risk of injury. Many studies assessed the prevalence of vitamin D deficiency in athletes; however, as of today, there are no official recommendations/protocols for screening vitamin D levels in athletes, and only a few studies were performed in male and female elite athletes (i.e., Olympic level), in different sport disciplines., Method: We investigated the prevalence of vitamin D deficiency among athletes entering the Israeli Olympic team. A total of 761 samples of Vitamin D(OH)25 from 334 athletes were analyzed. For this analysis, we used the first test the athlete had performed when joining the Olympic team. The prevalence of vitamin D deficiency (<50 nmol/L, as defined by the Endocrine Society Committee) was investigated according to gender, types of sports and outdoor vs. indoor sports through the different seasons of the Israeli Olympic team athletes., Result: Twenty-five athletes (7.5%) were diagnosed with vitamin D deficiency. One hundred and thirty-one athletes (39.2%) had insufficient levels of vitamin D (50-75 nmol/L). The highest incidence of vitamin D deficiency was found amongst gymnastics and combat sport athletes. A significant difference was also found in vitamin D concentration between seasons. Vitamin D average concentration in the winter was 74.1 nmol/L compared to 86.4 nmol/L in the Summer ( p < 0.0005)., Conclusions: Due to the importance of vitamin D to athletic performance and the high prevalence of deficiency and insufficiency, we suggest careful and frequent monitoring of groups at risk, including elite athletes, especially in susceptible sports and during the winter. Future studies are necessary to investigate the effectiveness of Vitamin D supplementation in athletes with low baseline vitamin D levels.

Background: Foot and ankle unloading is essential in various clinical contexts, including ulcers, tendon ruptures, and fractures. Choosing the right assistive device is crucial for functionality and recovery. Yet, research on the impact of devices beyond crutches, particularly ankle-foot orthoses (AFOs) designed to unload the ankle and foot, is limited. This study investigates the effects of three types of devices-forearm crutches, knee crutch, and AFO-on biomechanical, metabolic, and subjective parameters during walking with unilateral ankle-foot unloading., Methods: Twenty healthy participants walked at a self-selected speed in four conditions: unassisted able-bodied gait, and using three unloading devices, namely forearm crutches, iWalk knee crutch, and ZeroG AFO. Comprehensive measurements, including motion capture, force plates, and metabolic system, were used to assess various spatiotemporal, kinematic, kinetic, and metabolic parameters. Additionally, participants provided subjective feedback through questionnaires. The conditions were compared using a within-subject crossover study design with repeated measures ANOVA., Results: Significant differences were found between the three devices and able-bodied gait. Among the devices, ZeroG exhibited significantly faster walking speed and lower metabolic cost. For the weight-bearing leg, ZeroG exhibited the shortest stance phase, lowest braking forces, and hip and knee angles most similar to normal gait. However, ankle plantarflexion after push-off using ZeroG was most different from normal gait. IWalk and crutches caused significantly larger center-of-mass mediolateral and vertical fluctuations, respectively. Participants rated the ZeroG as the most stable, but more participants complained it caused excessive pressure and pain. Crutches were rated with the highest perceived exertion and lowest comfort, whereas no significant differences between ZeroG and iWalk were found for these parameters., Conclusions: Significant differences among the devices were identified across all measurements, aligning with previous studies for crutches and iWalk. ZeroG demonstrated favorable performance in most aspects, highlighting the potential of AFOs in enhancing gait rehabilitation when unloading is necessary. However, poor comfort and atypical sound-side ankle kinematics were evident with ZeroG. These findings can assist clinicians in making educated decisions about prescribing ankle-foot unloading devices and guide the design of improved devices that overcome the limitations of existing solutions., (© 2024. The Author(s).)

Risk of exertional heat stroke (EHS) is an ongoing challenge for United States military personnel, for athletes and for individuals with occupational stressors that involve prolonged activity in hot environments. Higher body mass index (BMI) is significantly associated with increased risk for EHS in activity duty U.S. Soldiers. During exercise, heat is generated primarily by contracting skeletal muscle (and other metabolically active body mass) and dissipated based on body surface area (BSA). Thus, in compensable environments, a higher BSA·mass -1 may be a benefit to heat dissipation and decrease the risk of EHS. The purpose of the present analysis was to test the hypothesis that BSA·mass -1 ratio is an important biophysical characteristic contributing to the risk of EHS. We employed a matched case-control approach, where each individual with a diagnosis of EHS was matched to five controls who were never diagnosed with EHS but were in the same unit and had the same job title. We used a multivariate conditional logistic regression model including variables of BSA·mass -1 , sex, age, military rank, and race. BSA·mass -1 significantly predicted EHS risk ( P = 0.006), such that people with higher BSA·mass -1 were at lower risk of developing EHS when controlling for other potential factors such as age and race. This relationship persisted after adjustment for other anthropometric measures of body size including weight, BMI, and BSA. These data suggest that biophysical factors play an important role in EHS risk, particularly in a healthy military-aged cohort of men and women. NEW & NOTEWORTHY With the impacts of climate change yielding higher average ambient temperatures over time, the incidence of EHS for individuals participating in outdoor activities may consequently increase. With the larger sample size in this study compared with prior research in this field, we were able to use various methods that had not been applied before. For example, we were able to mutually adjust for different measurements of body size to understand which metric had the highest association with EHS risk. Understanding factors that may be modifiable may be important for developing interventions to counteract the increased risk of EHS associated with climate change.

(1) Background: Cardiac rehabilitation often emphasizes aerobic capacity while overlooking the importance of muscle strength. This study evaluated the impact of an enhanced remote strength training program (RCR-ST) on cardiac rehabilitation. (2) Methods: In this randomized prospective study (RCT registration number SMC-9080-22), 50 patients starting cardiac rehabilitation were assessed for muscle strength, aerobic capacity, and self-reported outcomes at baseline and after 16 weeks. Participants were divided into two groups: the RCR-ST group received a targeted resistance training program via a mobile app and smartwatch, while the control group received standard care with general resistance training advice. (3) Results: The RCR-ST group demonstrated significant improvements in muscle endurance, notably in leg extension and chest press exercises, with increases of 92% compared to 25% and 92% compared to 13% in the control group, respectively. Functional assessments (5-STS and TUG tests) also showed marked improvements in agility, coordination, and balance. Both groups improved in cardiorespiratory fitness, similarly. The RCR-ST group reported enhanced physical health and showed increased engagement, as evidenced by more frequent use of the mobile app and longer participation in the rehabilitation program ( p < 0.05). (4) Conclusions: Incorporating a focused strength training regimen in remote cardiac rehabilitation significantly improves muscle endurance and patient engagement. The RCR-ST program presents a promising approach for optimizing patient outcomes by addressing a crucial gap in traditional rehabilitation protocols that primarily focus on aerobic training.

Background: A major threat in combat scenarios is the 'behind armor blunt trauma' (BABT) of a non-penetrating ballistic impact with a ballistic protective plate (BPP). This impact results in pressure waves that propagate through tissues, potentially causing life-threatening damage. To date, there is no standardized procedure for rapid virtual testing of the effectiveness of BPP designs. The objective of this study was to develop a novel, anatomically-accurate, finite element modeling framework, as a decision-making tool to evaluate and rate the biomechanical efficacy of BPPs in protecting the torso from battlefield-acquired non-penetrating impacts., Methods: To simulate a blunt impact with a BPP, two types of BPPs representing generic designs of threat-level III and IV plates, and a generic 5.56 mm bullet were modeled, based on their real dimensions, physical and mechanical characteristics (plate level-III is smaller, thinner, and lighter than plate level-IV). The model was validated by phantom testing., Results: Plate level-IV induced greater strains and stresses in the superficial tissues post the ballistic impact, due to the fact that it is larger, thicker and heavier than plate level-III; the shock wave which is transferred to the superficial tissues behind the BPP is greater in the case of a non-penetrating impact. For example - the area under volumetric tissue exposure histograms of strains and stresses for the skin and adipose tissues were 16.6-19.2% and 17.3-20.3% greater in the case of plate level-IV, for strains and stresses, respectively. The validation demonstrates a strong agreement between the physical phantom experiment and the simulation, with only a 6.37% difference between them., Conclusions: Our modelling provides a versatile, powerful testing framework for both industry and clients of BPPs at the prototype design phase, or for quantitative standardized evaluations of candidate products in purchasing decisions and bids., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

BACKGROUND: Exertional heatstroke affects athletes and soldiers and can lead to temporary heat intolerance. The heat tolerance test (HTT) was developed to assist in the return-to-duty decisions of military personnel. Although there are several possible causes for heat intolerance, a soldier who fails the test is prevented from returning to serve in a front-line combat unit, regardless of the underlying reason. CASE REPORT: A 19-yr-old special infantry male soldier with unremarkable medical history collapsed during an afternoon hand-to-hand combat training session in the gym. The medic on site promptly initiated inefficient tap water cooling and measured a rectal temperature of 38.7 °C; he returned to duty the same evening. A few weeks later, after intensive physical training, he experienced exhaustion during a stretcher-carrying foot march. He was referred by the unit's physician, who suspected a condition of heat intolerance, to an HTT. The soldier underwent two HTTs, which were found to be positive. Consequently, he was discharged from serving in his infantry unit. No congenital or functional underlying causes could explain the diagnosis of heat intolerance. DISCUSSION: We discuss the possibility that the only explaining cause for the two positive HTTs was the soldier's anthropometric measures, particularly the low body surface area to body weight ratio. We raise the question of whether this soldier could have been returned safely to duty. Rabotin A, Epstein Y, Ketko I. Heat intolerance, body size, and return to duty . Aerosp Med Hum Perform. 2023; 94(7):546-549.

Exposure to extreme environmental heat or cold during military activities can impose severe thermal strain, leading to impairments in task performance and increasing the risk of exertional heat (including heat stroke) and cold injuries that can be life-threatening. Substantial individual variability in physiological tolerance to thermal stress necessitates an individualized approach to mitigate the deleterious effects of thermal stress, such as physiological monitoring of individual thermal strain. During heat exposure, measurements of deep-body (T c ) and skin temperatures and heart rate can provide some indication of thermal strain. Combining these physiological variables with biomechanical markers of gait (in)stability may provide further insight on central nervous system dysfunction - the key criterion of exertional heat stroke (EHS). Thermal strain in cold environments can be monitored with skin temperature (peripheral and proximal), shivering thermogenesis and T c . Non-invasive methods for real-time estimation of T c have been developed and some appear to be promising but require further validation. Decision-support tools provide useful information for planning activities and biomarkers can be used to improve their predictions, thus maximizing safety and performance during hot- and cold-weather operations. With better understanding on the etiology and pathophysiology of EHS, the microbiome and markers of the inflammatory responses have been identified as novel biomarkers of heat intolerance. This review aims to (i) discuss selected physiological and biomechanical markers of heat or cold strain, (ii) how biomarkers may be used to ensure operational readiness in hot and cold environments, and (iii) present novel molecular biomarkers (e.g., microbiome, inflammatory cytokines) for preventing EHS., Competing Interests: Declaration of interest statement The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

We review the use of science by lawmakers and courts in implementing or rejecting legal rights for nature in Ecuador, India, the United States, and other jurisdictions where some type of rights of nature have been recognized in the legal system. We then use the "right to evolve" to exemplify how interdisciplinary work can (i) help courts effectively define what this right might entail; (ii) inform how it might be applied in different circumstances; and (iii) provide a template for how scientists and legal scholars can generate the interdisciplinary scholarship necessary to understand and implement the growing body of rights-of-nature laws, and environmental law more generally. We conclude by pointing to what further research is needed to understand and effectively implement the growing body of rights-of-nature laws.

Introduction: THE CLIMATE CRISIS.

Actions potentially harmful to the environment that are otherwise illegal are sometimes permitted in cases of emergency. How to define an emergency can therefore be both controversial and highly consequential. In this article, we explore one such contemporary controversy: when the use of neonicotinoid pesticides, banned in the EU, can nevertheless be granted an emergency authorization. We analyse several questions, currently before the EU Court of Justice in the ongoing Pesticide Action Network Europe and Others case, that will determine the scope of an "emergency" in the context of derogating from the Pesticide Regulation, and that may impact how "emergencies" are defined in other legal contexts. We argue that the circumstances do not support a legal finding that emergency authorization is justified in this case, and that, in general, "emergencies" must be narrowly defined when justifying measures that involve risks to human health and the environment., (© 2022. The Author(s).)

In a series of three companion papers published in this Journal, we identify and validate the available thermal stress indicators (TSIs). In this first paper of the series, we conducted a systematic review (registration: INPLASY202090088) to identify all TSIs and provide reliable information regarding their use (funded by EU Horizon 2020; HEAT-SHIELD). Eight databases (PubMed, Agricultural and Environmental Science Collection, Web of Science, Scopus, Embase, Russian Science Citation Index, MEDLINE, and Google Scholar) were searched from database inception to 15 April 2020. No restrictions on language or study design were applied. Of the 879 publications identified, 232 records were considered for further analysis. This search identified 340 instruments and indicators developed between 200 BC and 2019 AD. Of these, 153 are nomograms, instruments, and/or require detailed non-meteorological information, while 187 can be mathematically calculated utilizing only meteorological data. Of these meteorology-based TSIs, 127 were developed for people who are physically active, and 61 of those are eligible for use in occupational settings. Information regarding the equation, operating range, interpretation categories, required input data, as well as a free software to calculate all 187 meteorology-based TSIs is provided. The information presented in this systematic review should be adopted by those interested in performing on-site monitoring and/or big data analytics for climate services to ensure appropriate use of the meteorology-based TSIs. Studies two and three in this series of companion papers present guidance on the application and validation of these TSIs, to guide end users of these indicators for more effective use., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

Exposure to high ambient temperature is a stressor that influences both biological and behavioral functions and has been previously shown to have an extensive impact on brain structure and function. Physiological, cellular and behavioral responses to heat-stress (HS) (40-41 °C, 2 h) were evaluated in adult male Sprague-Dawley rats. The effect of HS exposure before predator-scent stress (PSS) exposure (i.e., HS preconditioning) was examined. Finally, a possible mechanism of HS-preconditioning to PSS was investigated. Immunohistochemical analyses of chosen cellular markers were performed in the hippocampus and in the hypothalamic paraventricular nucleus (PVN). Plasma corticosterone levels were evaluated, and the behavioral assessment included the elevated plus-maze (EPM) and the acoustic startle response (ASR) paradigms. Endogenous levels of heat shock protein (HSP)-70 were manipulated using an amino acid (L-glutamine) and a pharmacological agent (Doxazosin). A single exposure to an acute HS resulted in decreased body mass (BM), increased body temperature and increased corticosterone levels. Additionally, extensive cellular, but not behavioral changes were noted. HS-preconditioning provided behavioral resiliency to anxiety-like behavior associated with PSS, possibly through the induction of HSP-70. Targeting of HSP-70 is an attractive strategy for stress-related psychopathology treatment.

In a series of three companion papers published in this Journal, we identify and validate the available thermal stress indicators (TSIs). In this second paper of the series, we identified the criteria to consider when adopting a TSI to protect individuals who work in the heat, and we weighed their relative importance using a Delphi exercise with 20 experts. Two Delphi iterations were adequate to reach consensus within the expert panel (Cronbach's α = 0.86) for a set of 17 criteria with varying weights that should be considered when adopting a TSI to protect individuals who work in the heat. These criteria considered physiological parameters such as core/skin/mean body temperature, heart rate, and hydration status, as well as practicality, cost effectiveness, and health guidance issues. The 17 criteria were distributed across three occupational health-and-safety pillars: (i) contribution to improving occupational health (55% of total importance), (ii) mitigation of worker physiological strain (35.5% of total importance), and (iii) cost-effectiveness (9.5% of total importance). Three criteria [(i) relationship of a TSI with core temperature, (ii) having categories indicating the level of heat stress experienced by workers, and (iii) using its heat stress categories to provide recommendations for occupational safety and health] were considered significantly more important when selecting a TSI for protecting individuals who work in the heat, accumulating 37.2 percentage points. These 17 criteria allow the validation and comparison of TSIs that presently exist as well as those that may be developed in the coming years., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2022 Informa UK Limited, trading as Taylor & Francis Group.)

Purpose: Examine the effect of synthetic fabrics (SYN, 60% polyester: 40% nylon) vs. 100% cotton fabric (CTN) on the 20-km cycling time trial (20 kmCTT) performance of competitive cyclists and triathletes. Methods: In this randomized controlled crossover study, 15 adults (5 women) aged 29.6 ± 2.7 years (mean ± SE) with a peak rate of O 2 consumption of 60.0 ± 2.0 ml/kg/min completed a 20 kmCTT under ambient laboratory conditions (24.3 ± 0.7°C and 17 ± 7% relative humidity) with a simulated wind of ~3 m/s while wearing SYN or CTN clothing ensembles. Both ensembles were of snowflake mesh bi-layer construction and consisted of a loose-fitting long-sleeved shirt with full-length trousers. Results: Participants maintained a significantly ( p < 0.05) higher cycling speed and power output over the last 6-km of the 20 kmCTT while wearing the SYN vs. CTN ensemble (e.g., by 0.98 km/h and 18.4 watts at the 20-km mark). Consequently, 20 kmCTT duration was significantly reduced by 15.7 ± 6.8 sec or 0.8 ± 0.3% during SYN vs. CTN trials ( p < 0.05). Improved 20 kmCTT performance with SYN vs. CTN clothing could not be explained by concurrent differences in esophageal temperature, sweat rate, ratings of perceived exertion and/or cardiometabolic responses to exercise. However, it was accompanied by significantly lower mean skin temperatures (~1°C) and more favorable ratings of perceived clothing comfort and thermal sensation during exercise. Conclusion: Under the experimental conditions of the current study, athletic clothing made of synthetic fabrics significantly improved the 20 kmCTT performance of endurance-trained athletes by optimizing selected thermoregulatory and perceptual responses to exercise., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ferguson, Hadid, Epstein and Jensen.)

The effect of 30 days of β-alanine supplementation on neurophysiological responses of animals exposed to an acute heat stress (HS) was examined. Animals were randomized to one of three groups; exposed to HS (120 min at 40-41 °C) and fed a normal diet (EXP; n  = 12); EXP and supplemented with β-alanine (EXP + BA; n  = 10); or not exposed (CTL; n  = 10). Hippocampal (CA1, CA3 and DG) and hypothalamic (PVN) immunoreactive (ir) cell numbers of COX2, IBA-1, BDNF, NPY and HSP70 were analyzed. Three animals in EXP and one in EXP-BA did not survive the HS, however no significant difference ( p  = 0.146) was noted in survival rate in EXP + BA. The % change in rectal temperature was significantly lower ( p  = 0.04) in EXP + BA than EXP. Elevations ( p 's < 0.05) in COX-2, IBA-1 and HSP70 ir-cell numbers were noted in animals exposed to HS in all subregions. COX-2 ir-cell numbers were attenuated for EXP + BA in CA1 ( p  = 0.02) and PVN ( p  = 0.015) compared to EXP. No difference in COX-2 ir-cell numbers was noted between CTL and EXP + BA at CA1. BDNF-ir cell numbers in CA1, DG and PVN were reduced ( p 's < 0.05) during HS compared to CTL. No difference in BDNF-ir cell numbers was noted between EXP + BA and CTL in CA3 and PVN. NPY-ir density was reduced in exposed animals in all subregions, but NPY-ir density for EXP-BA was greater than EXP in CA3 ( p  < 0.001) and PVN ( p  = 0.04). β-Alanine supplementation attenuated the thermoregulatory and inflammatory responses and maintained neurotrophin and neuropeptide levels during acute HS. Further research is necessary to determine whether β-alanine supplementation can increase survival rate during a heat stress.

We tested whether salt preference increases immediately after exertion-induced Na + loss in sweat, and whether this may generalise to an increase in habitual dietary Na + intake. For the first aim, trained athletes (n = 20) exercised in 2 ambient temperatures and sweat Na + loss related to immediate salt preference assessed by taste, intake and psychophysical tests. For the second aim, we compared dietary and urinary Na + , and salt preference, seasoning and hedonics in the athletes and sedentary men (n = 20). No relationship was found between sodium loss during exercise and immediate preference for salt or psychophysical responses, and no differences in comparison to sedentary men. However, athlete diet had fewer foods (29.4 ± 1.5 vs 37.8 ± 1.9, p < 0.001), less seasoning (19 vs 32. p = 0.011) and more athletes reported dietary limitations (31 vs 11, p < 0.05), although nutrient content did not differ. Together these might suggest athlete adherence to a healthy diet at the expense of variety and flavour and a dissociation between dietary reports and intake. Athletes, more than controls, liked foods rich in energy and K + suggesting compensatory-driven hedonics, although overall their intake did not differ. The findings are consistent with the absence of a salt appetite responding to Na + loss in humans, and specifically that trained athletes do not increase their preference for salt in immediate response to exertion-induced Na + loss and are not at risk for increased dietary Na + compared to sedentary men., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Objective: To noninvasively explore the heat intolerance condition during exercise-heat stress by assessing cardiovascular (CV) performance., Design: Prospective study of participants undergoing a standard heat-tolerance test (HTT)., Setting: Institutional study., Participants: Ninety-five young males: 16 heat-intolerant (HI) and 79 heat-tolerant (HT)., Interventions: Cardiovascular performance during an HTT was estimated by heart rate (HR) and blood pressure measurements., Main Outcome Measures: The sensitivity of the cardiovascular reserve index (CVRI) and the dynamic heart rate reserve (dHRR) index to predict heat intolerance was compared., Results: A significant difference in the CV reserve during exercise-heat stress was exhibited between the HI and the HT groups. Starting at a similar level, the reduction in the CV reserve at HTT endpoint was much greater in the HI than the HT individuals (P < 0.0001), as depicted by both the CVRI and the dHRR. This result indicates a greater utilization of the CV reserve by HI individuals. The CVRI is likely to be better predictor of heat intolerance than the dHRR because the partial area under the curve in the high sensitivity (>90%) region of its receiver operating characteristic curve is higher (93.2 vs 76.8)., Conclusions: More than being a predictor, the CVRI may provide a new clinical insight into heat intolerance because it noninvasively characterizes the efficiency of an individual's thermoregulatory mechanism and hints that an impaired CV reserve might underlie heat intolerance. The CVRI provides a noninvasive measurement of thermoregulation, which has been long awaited to enable on-field studies and dynamic monitoring of heat-exposed task forces., Competing Interests: Gabbay has applied and issued a patent for CVRI method. The other authors report no conflict of interest., (Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Even with the advent of the COVID-19 vaccine, masks and social distancing are recommended as a precautionary measure to suppress SARS-CoV-2 infection and disease. In Israel, as in many other countries, despite official regulations and widespread availability and accessibility to affordable effective masks, the use of face masks is not consistent or universal. Physicians and other medical and health professionals have a vital role to play in communicating to the public about the importance of masking and encouraging people to wear face masks correctly and consistently. This review underscores the importance of masking as a protective public health mitigation measure. It describes types of face masks mainly used by the public and their effectiveness. It emphasizes the importance of identifying and addressing barriers (e.g., physical, social, economic) to encourage widespread and sustained appropriate use of masks. The article also proposes strategies to enhance masking, such as changing social norms through targeted local interventions and governmental control of mask quality and price.

Athletes, soldiers, and workers who perform intense physical activities under extreme hot conditions might encounter increased physiological thermal strain. Consequently, the increase in body core temperature (T c ) might result in heat exhaustion and heatstroke. Thus, continuously following changes in T c is of utmost importance. Recently, the Tcore sensor (Dräger, Germany), which employs a unique dual-sensor heat flux technology, became commercially available to measure T c , in a hospital-controlled environment. This study aimed to evaluate the possibility of using the Tcore sensor to accurately monitor rectal temperature (T re ), reflecting T c , under exercise-heat stress. Thirteen healthy young males completed the study protocol, consisting of 90 min of moderate exercise (walking on a treadmill - 5 km/h, 4% elevation) under controlled hot/dry and hot/wet climatic conditions (30 °C/60% rh, 34 °C/40% rh, and 40 °C/40% rh). Tcore sensors were placed on the forehead and the left wrist. Temperatures from both Tcore sensors were recorded continuously together with T re using a rectal thermistor. The original algorithm used by the company to estimate T re from the Tcore sensor was found to be inadequate under the study's conditions and new models for the forehead and the wrist measurements were developed. Nearly 150,000 measurement sets (after filtering) were used to build independent MATLAB software algorithms and test their reliability according to the cross-validation algorithm. Bland-Altman analysis was used to compare between the results obtained by the new models to T re . The database consisted of a large T re range (36.5-38.9 °C). The mean errors of the models were close to zero, and the mean absolute errors were 0.20 ± 0.16 °C and 0.27 ± 0.20 °C for the forehead and wrist, respectively. 95% of the measurements from the forehead model and 86% from the wrist model were within ±0.5 °C of T re , and 78% (forehead) and 64% (wrist) were within ±0.3 °C. Root Mean Square Deviation (RMSD) values were 0.29 °C and 0.40 °C for the forehead and wrist models, respectively. The developed models show the feasibility to use the Tcore sensor for assessing T re under exercise-heat conditions. Furthermore, the sensor was found to be adequate for use on the wrist as well, which might be more practical for use in field conditions., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Benefits obtained after heat acclimation/acclimatization should be completely lost after an estimated period of 6 weeks. However, this estimate is still hypothetical. We evaluate the long-term effects of heat acclimatization on the level of heat tolerance. Physiological and subjective markers of heat tolerance were assessed during a heat stress test (HST: 3 × 8-min runs outdoors [~ 40 °C and 20% RH] at 50% of their estimated speed at VO 2max ) performed on the 2nd day upon arrival to the desert military base in the United Arab Emirates after a first day of mostly passive exposure to heat. Among the 50 male French soldiers, 25 partook in a 4-month military mission in countries characterized by a hot environment ~ 6 months prior to the study (HA). The other 25 participants were never heat acclimatized (CT). Rectal temperature (p = 0.023), heart rate (p = 0.033), and perceived exertion (p = 0.043) were lower in the HA than CT group at the end of HST. Soldiers who experienced a former 4-month period of natural heat acclimatization very likely had a higher level of heat tolerance during exercise in the heat, even 6 months after returning from the previous desert mission, than that of their non-acclimatized counterparts.

Objective: Researchers have produced a hypothesis of transient heat intolerance (HI) after exertional heat stroke (EHS). Based on this hypothesis, heat-tolerance testing (HTT) has been postponed until weeks 6 to 8 after EHS and other types of exertional heat illness (EHI). We compared the HTT results of participants after either EHS or other EHI who were tested earlier (≤6-week group) versus those who were tested later (>6-week group) to verify the hypothesis., Design: Cohort study., Setting: Data obtained from records of military athletes who experienced EHS or EHI., Patients or Other Participants: All participants who underwent HTT after EHI or EHS experienced between 2014 and 2018 and for whom complete data regarding the severity of the event (rectal temperature, neurologic symptoms, and laboratory results) and HTT results were available were included. Participants with suspected EHS and those with other EHIs were evaluated separately., Main Outcome Measure(s): The percentages of participants with HI and mean probability of heat tolerance were compared between those tested within 6 weeks of the event and those tested later., Results: A total of 186 participants were included in this study (EHS: 12 in the <6-week group, 9 in the >6-week group; EHI: 94 in the <6-week group, 71 in the >6-week group). In the EHS group, the percentages with HI (33% versus 44%, P = .67) and mean probability of heat tolerance (0.82 versus 0.82, P = .98) did not differ. In the EHI group, participants who were tested after 6 weeks had a greater chance of being diagnosed with HI (38% versus 21.3%, P < .02)., Conclusions: The HTT results were similar between participants with EHS who were tested early (<6 weeks) and those tested late (>6 weeks). Further investigation of heat-tolerance changes in larger cohorts of patients after EHS is required to verify the theory of transient HI.

Temperature increases due to climate changes and operations expected to be conducted in hot environments make heat-related injuries a major medical concern for the military. The most serious of heat-related injuries is exertional heat stroke (EHS). EHS generally occurs when health individual perform physical activity in hot environments and the balance between body heat production and heat dissipation is upset resulting in excessive body heat storage. Blood flow to the skin is increased to assist in dissipating heat while gut blood flow is considerably reduced, and this increases the permeability of the gastrointestinal mucosa. Toxic materials from gut bacteria leak through the gastrointestinal mucosa into the central circulation triggering an inflammatory response, disseminated intravascular coagulation (DIC), multiorgan failure, and vascular collapse. In addition, high heat directly damages cellular proteins resulting in cellular death. In the United States military, the overall incidence of clinically diagnosed heat stroke from 1998 to 2017 was (mean ± standard deviation) 2.7 ± 0.5 cases/10,000 Soldier-years and outpatient rates rose over this period. The cornerstone of EHS diagnosis is recognition of central nervous dysfunction (ataxia, loss of balance, convulsions, irrational behavior, unusual behavior, inappropriate comments, collapse, and loss of consciousness) and a body core temperature (obtained with a rectal thermometer) usually >40.5°C (105°F). The gold standard treatment is whole body cold water immersion. In the field where water immersion is not available it may be necessary to use ice packs or very cold, wet towels placed over as much of the body as possible before transportation of the victim to higher levels of medical care. The key to prevention of EHS and other heat-related injuries is proper heat acclimation, understanding work/rest cycles, proper hydration during activity, and assuring that physical activity is matched to the Soldiers' fitness levels. Also, certain dietary supplements (DSs) may have effects on energy expenditure, gastrointestinal function, and thermoregulation that should be considered and understood. In many cases over-motivation is a major risk factor. Commanders and trainers should be alert to any change in the Soldier's behavior. Proper attention to these factors should considerably reduce the incidence of EHS., (2019.)

Background: The rate of eye injury is steadily rising during military conflicts of the century, with thermal burns being the most common type of injury to the eyes. The present study focuses on assessing the heat resistance properties of military protective goggles using three-dimensional (3D) finite element head modeling fitted with the tested protective gear., Methods: A computational thermal impact was applied onto a 3D biomimetic human head model fitted with two goggle models - sports (Type 1) and square (Type 2). The resultant temperature of the eye tissues and the thermal injury thresholds were calculated by using the modeling, hence allowing to determine the protective efficacy of the goggles objectively, in a standardized, quantitative and cost-effective manner., Findings: Both types of goggles had a dramatic protective effect on the eyes. The specific goggle geometry had no notable effect on the level of protection to the inner tissues against the thermal insult. At the skin level goggles reduced temperatures by ~64% under the impact zone, with only a mild difference (10 °C) between the goggles., Interpretation: Little limitations on the shape and geometry of goggles were observed and any structure of goggles can provide an adequate protection against a thermal insult (per se) to inner cranial tissues, assuming the lenses are wide and thick enough to block direct skin contact of the heat insult. It was shown that our 3D biomimetic human head model provides a practical and cost-effective tool for determining the performance level of goggles with different attributed (i.e., shapes and thermal properties)., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objectives: Manual ventilation of intubated patients is a common intervention. It requires skill as well as physical effort and is typically restricted to brief periods. Prolonged manual ventilation may be unavoidable in some scenarios, for example, extreme mass casualty incidents. The present study tested whether nurses are capable of appropriately manually ventilating patients for 6 hours., Design: Volunteers performed ventilation on an electronic simulator for 6 hours while their own cardiorespiratory variables and the quality of the delivered ventilation were measured and recorded. The volunteers scored their perceived level of effort on a standard Borg Scale., Setting: Research laboratory at the Emergency Department, Tel Aviv Medical Center., Subjects: Ten nursing staff members of the Tel Aviv Sourasky Medical Center, 25-43 years old., Interventions: Volunteers ventilated manually a lung simulator for 6 hours., Measurements and Main Results: The subjects' physiologic states, including blood pressure, heart rate, respiratory rate, and oxygen saturation, showed no significant changes over time. The quality of delivered ventilation was somewhat variable, but it was stable on the average: average tidal volume ranged between 524.8 and 607.0 mL (p = 0.33). There was a slight but significant increase (7.3-10.9 L/min [p = 0.048]) in minute volume throughout the test period, reaching values consistent with mild hyperventilation. The subjects scored their perceived working effort as very light to fairly light, with a nonsignificant gradual increase in the Borg score as the study progressed., Conclusions: Manual ventilation of intubated patients can be performed continuously for 6 hours without excessive physical effort on the part of the operator. The quality of delivered ventilation was clinically adequate for all of them. There was a mild but significant trend toward hyperventilation, albeit within safe clinical levels, which was due to an increasing ventilatory rate rather than an increase in tidal volume.

Despite the progress in developing personal combat-protective gear, eye and brain injuries are still widely common and carry fatal or long-term repercussions. The complex nature of the cranial tissues suggests that simple methods (e.g. crash-dummies) for testing the effectiveness of personal protective gear against non-penetrating impacts are both expensive and ineffective, and there are ethical issues in using animal or cadavers. The present work presents a versatile testing framework for quantitatively evaluating protective performances of head and eye combat-protective gear, against non-penetrating impacts. The biomimetic finite element (FE) head model that was developed provides realistic representation of cranial structure and tissue properties. Simulated crash impact results were validated against a former cadaveric study and by using a crash-phantom developed in our lab. The model was then fitted with various helmet and goggle designs onto which a non-penetrating ballistic impact was applied. Example data show that reduction of the elastic and shear moduli by 30% and 80% respectively of the helmet outer Kevlar-29 layer, lowered intracranial pressures by 20%. Our modeling suggests that the level of stresses that develop in brain tissues, which ultimately cause the brain damage, cannot be predicted solely by the properties of the helmet/goggle materials. We further found that a reduced contact area between goggles and face is a key factor in reducing the mechanical loads transmitted to the optic nerve and eye balls following an impact. Overall, this work demonstrates the simplicity, flexibility and usefulness for development, evaluation, and testing of combat-protective equipment using computational modeling. Highlights A finite element head model was developed for testing head gear. Reduced helmet's outer layer elastic and shear moduli lowered intracranial stresses. Gear material properties could not fully predict impact-related stress in the brain. Reduced goggles-face contact lowered transmitted loads to the optic nerve and eyes.

Stress fractures (SF) are one of the most common and potentially serious overuse injuries., Purpose: This study aimed to develop a computational biomechanical model of strain in human tibial bone that will facilitate better understanding of the pathophysiology of SF., Methods: The MRI of a healthy, young male was used for full anatomical segmentation of the calf tissues, which considered hard-soft tissues biomechanical interactions. From the undeformed coronal MR images, the geometry of bones, muscles, connecting ligaments, and fat were reconstructed in three dimensions and meshed to a finite element model. A force that simulated walking was applied on the tibial plateaus. The model was then analyzed for strains in the tibia under various conditions: unloaded walking, walking with a load equivalent to 30% of bodyweight, and walking under conditions of muscular fatigue. In addition, the effect of tibia robustness on strain was analyzed., Results: The model showed that the tibia is mostly loaded by compression, with maximal strains detected in the distal anterior surface: 1241 and 384 microstrain, compressive and tensile, respectively. Load carriage resulted in ~30% increase in maximal effective strains. Muscle fatigue has a complex effect; fatigued calf muscles (soleus) reduced the maximal effective strains up to 9%, but fatigued thigh muscles increased those strains by up to 3%. It had also been shown that a slender tibia is substantially prone to higher maximal effective strains compared with an average (22% higher) or robust tibia (39% higher)., Conclusions: Thigh muscle fatigue, load carriage, and a slender tibia were detected as factors that may contribute to the development of SF. The methodology presented here is a novel tool for investigating the pathophysiology of SF.