Influences of Female Sex and Reproductive Hormones on Physiological Aspects of Heat Acclimation (NCT05292170) | Clinical Trial Compass
CompletedNot Applicable
Influences of Female Sex and Reproductive Hormones on Physiological Aspects of Heat Acclimation
United States27 participantsStarted 2021-10-01
Plain-language summary
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.
Who can participate
Age range
18 Years – 40 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* • Males and females, age 18-40 y (17 y for active duty military)
* Eumenorrheic females (menstrual cycle length between 24-35 days) or females taking oral contraceptives
* In good health as determined by OMSO (Office of Medical Support and Oversight) General Medical Clearance and willing to report all medications and dietary supplements (i.e. cold medication, Tylenol. Aleve) to the PI and OMSO.
* Passed his/her most recent Army Combat Fitness Test (ACFT) (military volunteers only) or exercise at least 2 times per week (civilian volunteers)
* Willing to not exercise, or drink alcoholic beverages for 24 hours before each testing session
* Willing to not consume caffeine 12 hours prior to any testing sessions
* Willing to refrain from additional moderate to strenuous physical activity throughout testing period
* Males and females with BMI \<30
Exclusion Criteria:
* • Females who are pregnant or planning to become pregnant during the study
* Females utilizing implantable contraception (intrauterine device, implantable bar)
* Tested positive for COVID-19 within the past 30 days.
* Taking prescription or over the counter medication, other than a contraceptive (unless approved by OMSO and Principal Investigator (PI))
* Tobacco users, or anyone who has used tobacco within the last four months
* Physical problems/injuries that would affect walking or running on a treadmill
* Allergy to skin adhesive
* Heart, lung, kidney, muscle, …
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Core temperature
Timeframe: 10 days
2
Heart rate
Timeframe: 10 days
Trial details
NCT IDNCT05292170
SponsorUnited States Army Research Institute of Environmental Medicine