The impact of a 20-h rotating watch schedule on cognitive and mood states in submarine operations.

This is the first study to provide valuable insights into the effects of the Israeli Navy's 20-h rotating watch schedule on submariners' alertness, mood states, risk-taking behaviours, and sleep. Specifically, we assessed the impact of the non-circadian-aligned schedule on cognitive performance, mood, and behavioural outcomes in a highly controlled submarine environment. A total of 20 male submariners participated in an at-sea mission, where their cognitive performance, mood states, risk-taking propensity, and caffeine consumption were measured.

The Significance of Body Surface Area to Mass Ratio for Thermal Responses to a Standardized Exercise-Heat Stress Test.

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.

caffeine consumption, cognitive performance, and sleep in special forces soldiers during a 96-h combat exercise.

Introduction: This observational study investigated the effects of sleep deprivation and ad libitum caffeine consumption on cognitive performance, risk behavior, and mood among 28 Israeli Special Forces (SF) soldiers (mean age: 20.57 ± 0.92 years) during a 96-hour combat exercise.

Musculoskeletal injuries in military personnel-Descriptive epidemiology, risk factor identification, and prevention.

Objectives: To provide an overall perspective on musculoskeletal injury (MSI) epidemiology, risk factors, and preventive strategies in military personnel.

Design: Narrative review.

Methods: The thematic session on MSIs in military personnel at the 5th International Congress on Soldiers' Physical Performance (ICSPP) included eight presentations on the descriptive epidemiology, risk factor identification, and prevention of MSIs in military personnel.

Assessing rectal temperature with a novel non-invasive sensor.

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) might result in heat exhaustion and heatstroke. Thus, continuously following changes in T is of utmost importance.

Mild Physical Activity Does Not Improve Spatial Learning in a Virtual Environment.

It is well-established that physical exercise in humans improves cognitive functions, such as executive functions, pattern separation, and working memory. It is yet unknown, however, whether spatial learning, long known to be affected by exercise in rodents, is also affected in humans. In order to address this question, we recruited 20 healthy young male adults (18-30 years old) divided into exercise and control groups ( = 10 in each group).

Cognitive Effects of Astaxanthin Pretreatment on Recovery From Traumatic Brain Injury.

Traumatic brain injury (TBI), caused by mechanical impact to the brain, is a leading cause of death and disability among young adults, with slow and often incomplete recovery. Preemptive treatment strategies may increase the injury resilience of high-risk populations such as soldiers and athletes. In this work, the xanthophyll carotenoid Astaxanthin was examined as a potential nutritional preconditioning method in mice (sabra strain) to increase their resilience prior to TBI in a closed head injury (CHI) model.

Sex Differences in Human Thermoregulation: Relevance for 2020 and Beyond.

The participation of women in physically strenuous athletic and occupational tasks has increased substantially in the past decade. Female sex steroids have influences on thermoregulatory processes that could impact physical performance in the heat. Here, we summarize and evaluate the current literature regarding sex differences in thermoregulation and provide recommendations for heat-illness risk-mitigation strategies.

Correction to: Astaxanthin supplementation impacts the cellular HSP expression profile during passive heating.

Due to an unfortunate misunderstanding, the top part of Figures 2 and 3 are not correctly displayed. The original article has been corrected and the proper version of Figures 2 and 3 is also published here.

When Should a Heat-Tolerance Test Be Scheduled After Clinical Recovery From an Exertional Heat Illness?

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.

Astaxanthin supplementation impacts the cellular HSP expression profile during passive heating.

Astaxanthin is a powerful carotenoid antioxidant prevalent in marine organisms and approved as a food supplement. Recent studies have demonstrated Astaxanthin's beneficial attributes in various health states. Following initial reports of potential heat protective properties in Astaxanthin supplemented rats, we present here results of a novel study examining the effect of Astaxanthin supplementation on the heat shock response in rats in relation to core temperature (Tc) and the ensuing physiological strain.

Asthaxanthin Improves Aerobic Exercise Recovery Without Affecting Heat Tolerance in Humans.

To examine the supplementation effects of the xanthophyll carotenoid Astaxanthin on physical performance and exertional heat strain in humans. A randomized double blind placebo controlled trial. Twenty two male participants (Age: 23.

The relation between central variables, electromyography signals and peripheral microcirculation during intensive treadmill exercise.

Background: Aerobic exercise under muscle fatigue can lead to muscular damage and injuries. Finding the correlations between central and peripheral microcirculation variables, as well as with electromyography signals of leg muscles during aerobic exercise, may contribute to early muscle fatigue identification. The goal of this study was to characterize the peripheral compensation following intensive exercise for assessment of muscle performance based on non-invasive techniques.

The Cardiovascular Reserve Index-A Noninvasive Clinical Insight Into Heat Intolerance.

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.

Probability of Heat Intolerance: Standardized Interpretation of Heat-Tolerance Testing Results Versus Specialist Judgment.

Context:   The heat-tolerance test (HTT) is a screening tool for secondary prevention of exertional heat illness by the Israel Defense Forces. To discern participant tolerance, recruits are exposed to intermediate environmental and exercise stresses, and their physiological responses, core temperature, and heart rate are monitored. When their physiological measures rise at a higher rate or exceed the upper levels of absolute values compared with other participants, heat intolerance (HI) is diagnosed.

Individualized estimation of human core body temperature using noninvasive measurements.

A rising core body temperature (T) during strenuous physical activity is a leading indicator of heat-injury risk. Hence, a system that can estimate T in real time and provide early warning of an impending temperature rise may enable proactive interventions to reduce the risk of heat injuries. However, real-time field assessment of T requires impractical invasive technologies.

The validity of the heat tolerance test in prediction of recurrent exertional heat illness events.

Objectives: Heat-tolerance-testing (HTT) protocol is used as a screening test for secondary prevention of exertional heat illness (EHI) in the military. Subjects whose test results are positive (heat-intolerant, HI) are presumed to be at higher risk of repeated EHI events than heat-tolerant subjects (HT) and are therefore prevented from return to combat duty, but may return to unsupervised recreational activity. Our aim was to determine, whether HTT results predict the risk of repeated episodes of exertional heat illness (EHI).

The role of adaptive bone formation in the etiology of stress fracture.

Stress fractures are common injuries with load-bearing activities. Stress fractures have been reported in the scientific literature for over a century; however, the etiology continues to be investigated with important distinctions made between the contributions of the tissue-level processes of bone remodeling and modeling. In response to novel repetitive loading, increased bone remodeling may serve to replace fatigue-damaged bone while at the same time creating temporary porosity.

Effects of basic combat training on iron status in male and female soldiers: a comparative study.

Objective: Iron is an essential micronutrient known to affect physical and cognitive performance. Studies indicate a significant reduction in iron status in female Soldiers immediately following military training, although the comparative effects of military training on iron status between male and female Soldiers have not been examined. The objective of this study was to compare the longitudinal effects of US Army basic combat training (BCT) on iron status indicators in a group of male and female Soldiers.

The correlation between postural control and upper limb position sense in people with chronic ankle instability.

Background: Chronic ankle instability (CAI) is attributed to functional instability driven by insufficient proprioception. However, it is not clear whether the deficits are related to global impaired performance or to specific decrease in ankle motor-control. The aim of this study was to assess the correlation between lower limb postural control and upper limb position sense among people with CAI, in order to further explore the function of the central neural control in people with CAI.

Heat tolerance after total and partial acute sleep deprivation.

Sleep deprivation (SD) is suggested to be associated with reduced thermo-regulatory functions. This study aimed to quantify the effect of partial (PSD) and total (TSD) 24 h SD using a standard heat tolerance test (HTT). Eleven participants underwent HTT after well-rested state, PSD and TSD.

Heat tolerance testing: association between heat intolerance and anthropometric and fitness measurements.

This study investigated associations between heat intolerance, as determined by performance on a heat tolerance test (HTT), and anthropometric measurements (body surface-to-mass ratio, percent body fat, body mass index, and waist circumference) and cardiorespiratory fitness (maximal oxygen uptake [VO2max]). Relationships between predictive variables and specific physiological measurements recorded during the HTT were examined. A total of 34 male and 12 female participants, recruited from the military community, underwent anthropometric measurements, a maximal aerobic exercise test, and a standardized HTT, which consisted of walking on a treadmill at 5 km/h at 2% grade for 120 minutes at 40°C and 40% relative humidity.

Evaluation of the performance of females as light infantry soldiers.

A few countries permit women to serve in combat roles, but their long term performance in these positions has not been reported. The incidences of overuse injuries and attrition of 85 male and 235 female recruits in a light infantry brigade was followed in a three-year prospective study. Females were shorter (162 cm, CI 161-163 cm) than males (174 cm, CI 173-176), had more body fat (18.