Effect of Serial Pregnancies on Physical Fitness.

Introduction: Pregnancy has a profound impact on physical fitness, and delivery does not allow for rapid return to peak performance levels as physiologic changes can persist for greater than 1 year postpartum. Multiple studies across all military services have documented decrements in physical performance with pregnancy among women. The purpose of this study was to determine the impact of serial pregnancies on physical fitness and body composition in a cohort of Army women.

The Role of Motivation to Excel in the Etiology of Exertional Heat Stroke.

Exertional heat stroke (EHS) is a medical emergency characterized by elevated body temperature and central nervous system dysfunction, and it can include dizziness, confusion and loss of consciousness, as well as long-term organ and tissue damage. EHS is distinct from classic, or passive, heat stroke and is most commonly observed during intense physical activity in warfighters, athletes, and laborers. EHS is an ongoing non-combat threat that represents a risk to both the health and readiness of military personnel.

Beating the heat: military training and operations in the era of global warming.

Global climate change has resulted in an increase in the number and intensity of environmental heat waves, both in areas traditionally associated with hot temperatures and in areas where heat waves did not previously occur. For military communities around the world, these changes pose progressively increasing risks of heat-related illnesses and interference with training sessions. This is a significant and persistent "noncombat threat" to both training and operational activities of military personnel.

Cooling Modality Effectiveness and Mortality Associate With Prehospital Care of Exertional Heat Stroke Casualities.

Background: Cold-water immersion is the gold standard for field treatment of an exertional heat stroke (EHS) casualty. Practical limitations may preclude this method and ice sheets (bed linens soaked in ice water) have emerged as a viable alternative. Laboratory studies suggest that this is an inferior method; however, the magnitude of hyperthermia is limited and may underestimate the cooling rate in EHS casualties.

Exertional heat stroke: an evidence based approach to clinical assessment and management.

New Findings: What is the topic of this review? The treatment of exertional heat stress, from initial field care through the return-to-activity decision. What advances does it highlight? Clinical assessment during field care using AVPU and vital signs to gauge recovery, approaches to field cooling and end of active cooling, and shared clinical decision making for return to activity recommendations.

Abstract: Exertional heat stroke (EHS) is a potentially fatal condition characterized by central nervous system (CNS) dysfunction and body temperature often but not always >40°C that occurs in the context of physical work in warm or hot environments.

Heat Safety in the Workplace: Modified Delphi Consensus to Establish Strategies and Resources to Protect the US Workers.

The purpose of this consensus document was to develop feasible, evidence-based occupational heat safety recommendations to protect the US workers that experience heat stress. Heat safety recommendations were created to protect worker health and to avoid productivity losses associated with occupational heat stress. Recommendations were tailored to be utilized by safety managers, industrial hygienists, and the employers who bear responsibility for implementing heat safety plans.

The effect of pregnancy and the duration of postpartum convalescence on the physical fitness of healthy women: A cohort study of active duty servicewomen receiving 6 weeks versus 12 weeks convalescence.

Introduction: Pregnancy profoundly affects cardiovascular and musculoskeletal performance requiring up to 12 months for recovery in healthy individuals.

Objective: To assess the effects of extending postpartum convalescence from 6 to 12 weeks on the physical fitness of Active Duty (AD) soldiers as measured by the Army Physical Fitness Test (APFT) and Body Mass Index (BMI).

Methods: We conducted a retrospective study of AD soldiers who delivered their singleton pregnancy of ≥ 32weeks gestation at a tertiary medical center.

Seasonal Trends for Environmental Illness Incidence in the U.S. Army.

Introduction: The incidence of and risk factors for exertional heat illness (EHI) and cold weather injury (CWI) in the U.S. Army have been well documented.

Body mass index predicts selected physical fitness attributes but is not associated with performance on military relevant tasks in U.S. Army Soldiers.

Objectives: Army body composition standards are based upon validated criteria; however, certain field-expedient methodologies (e.g., weight-for-height, body mass index [BMI]) may disqualify individuals from service who may otherwise excel on physical performance and military-relevant tasks.

Fitness tests and occupational tasks of military interest: a systematic review of correlations.

: Physically demanding occupations (ie, military, firefighter, law enforcement) often use fitness tests for job selection or retention. Despite numerous individual studies, the relationship of these tests to job performance is not always clear. : This review examined the relationship by aggregating previously reported correlations between different fitness tests and common occupational tasks.

Validity of Self-Reported Physical Fitness and Body Mass Index in a Military Population.

Many epidemiological studies rely on valid physical fitness data. The purpose of this investigation was to assess the validity of self-reported Army Physical Fitness Test (APFT) data and determine whether men and women recall APFT performance differently. U.

Impact of Arm Immersion Cooling During Ranger Training on Exertional Heat Illness and Treatment Costs.

Unlabelled: Ranger training includes strenuous physical activities and despite heat mitigations strategies, numerous cases of serious exertional heat illness (EHI) occur. We developed an Arm Immersion Cooling (AIC) system that is not logistically burdensome and may be easily employed in training environments.

Purpose: To examine the effect of AIC on EHI incidence, severity, and treatment costs during Ranger School.

Cold thermoregulatory responses following exertional fatigue.

Participants in prolonged, physically demanding cold-weather activities are at risk for a condition called "thermoregulatory fatigue". During cold exposure, the increased gradient favoring body heat loss to the environment is opposed by physiological responses and clothing and behavioral strategies that conserve body heat stores to defend body temperature. The primary human physiological responses elicited by cold exposure are shivering and peripheral vasoconstriction.

Evidence against a 40 degrees C core temperature threshold for fatigue in humans.

Evidence suggests that core temperatures of approximately 40 degrees C can induce fatigue, although this may be confounded by coincident elevations in skin temperatures and maximal cardiovascular strain. In an observational field study to examine core temperature threshold for fatigue, we investigated whether running performance is impaired when rectal temperature (T(re)) is >40 degrees C and skin temperature remains modest. Seventeen competitive runners (7/10 women/men: 8 km best 1,759 +/- 78/1,531 +/- 60 s) completed 8-km track time trials in cool (WBGT approximately 13 degrees C; n = 6), warm (WBGT approximately 27 degrees C; n = 4), or both (n = 7) conditions.

A simple and valid method to determine thermoregulatory sweating threshold and sensitivity.

Sweating threshold temperature and sweating sensitivity responses are measured to evaluate thermoregulatory control. However, analytic approaches vary, and no standardized methodology has been validated. This study validated a simple and standardized method, segmented linear regression (SReg), for determination of sweating threshold temperature and sensitivity.

Thermal response to running across the Sahara desert: data for three men.

Background: There are limited data concerning the physiological responses to long-duration exercise collected under field conditions, and less data under harsh environmental conditions. This paper describes select environmental conditions and physiological responses of three runners attempting to run across the entire Sahara desert over a 111-d period.

Methods: The runners started in Saint-Louis, Senegal, and we collected data on 2 d at the start of the expedition.