2 Clinical Trials for Various Conditions
Women are often understudied in thermal physiology research, leaving recommendations for Soldier safety and performance in hot conditions based largely on data collected in men. Female sex hormones estradiol and progesterone clearly have non-reproductive physiological effects, including influences on thermoregulatory and cardiovascular function. However, mechanisms of differing physiological adaptations to repeated heat exposure (i.e., heat acclimation) as a function of reproductive hormone status have yet to be investigated in a systematic way. Understanding possible sex differences in adaptation or mechanisms for adaptation during heat acclimation is important to ultimately optimize interventions to maximize soldier health and safety during training and deployment in the heat. Our goals in the present study are to evaluate physiological and biophysical responses to a standard heat acclimation protocol in a group of young, healthy men and women. Thirty individuals (n=10 males, n=10 women with a low hormonal status (i.e. early follicular phase), n=10 women with a high hormonal status (i.e. midluteal phase)) will complete 10 consecutive days of exercise (treadmill walking: 3.1 mph/2% grade) in the heat (40°C /40% relative humidity) up to 3hr per day. Changes in core temperature, heart rate, and sex hormones will be assessed to examine differences in thermoregulatory response to heat acclimation.
The purpose of this study is to determine whether dietary quercetin supplementation effects thermotolerance and heat acclimation in human subjects exposed to exercise/heat stress. Specific Aim I. To determine if quercetin in combination with repeated bouts of thermally stressful exercise will impact intestinal barrier function. The investigators will examine urinary lactulose excretion, plasma endotoxin,plasma quercetin, inflammatory cytokines (TNF-a \& Il-6), anti-inflammatory cytokines (Il-10), and HSP70 and HSF-1 content of peripheral blood mononuclear cells. Specific Aim II. To determine whether quercetin's suppresses the ability of human subjects to acclimate to exercise/heat stress. The investigators will examine body temperatures, heart rates, physiological strain, sweat and plasma volume responses to standardized heat tolerance tests.