Acute Exercise With Overdressing

NCT ID: NCT07080853

Last Updated: 2025-12-24

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 23 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-06-22
• Study Completion Date: 2025-04-28

Brief Summary

The purpose of this study is to determine if exercise with extra clothing in a gym-like environment can increase body temperatures appropriately to help people adapt to the heat.

Detailed Description

The purpose of the present study is to examine the influence of a novel 90-minute exercise + overdressing protocol on thermal responses in comparison to matched exercise in standard PT clothing. Sixteen healthy and fit adults (8 men and 8 women) will complete two 90-minute exercise sessions (randomized order) in a temperate environment (~20°C, ~50% relative humidity, and ~1 mph air velocity) involving a 30-minute run immediately followed by a 60-minute walk. Participants will wear standard physical training (PT) clothing (shorts, t-shirt) during one session and an overdressing ensemble in the other. The investigators hypothesize that 1) exercise + overdressing will elevate core temperature to between 38.3°C and 39.3°C for at least 45 minutes; and 2) elevations in core temperature, skin temperature, heart rate, and sweat rate will be substantially larger than observed with 90 minutes of matched exercise in standard PT clothing.

Conditions

Heat Stress, Exertional; Heat Acclimation and Thermotolerance

Keywords

Heat acclimation; Overdressing

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: OTHER
• Blinding Strategy: NONE

Study Groups

Exercise with Overdressing

Exercise with overdressing clothing ensemble

Group Type: EXPERIMENTAL

Exercise with Overdressing

Intervention Type: OTHER

Run for 30 minutes followed by walk for 60 minutes in a temperate (gym-like environment) wearing overdressing ensemble.

Control Exercise

Exercise with normal attire

Group Type: ACTIVE_COMPARATOR

Control Exercise

Intervention Type: OTHER

Run for 30 minutes followed by walk for 60 minutes in a temperate (gym-like environment) wearing control clothing ensemble.

Interventions

Exercise with Overdressing

Run for 30 minutes followed by walk for 60 minutes in a temperate (gym-like environment) wearing overdressing ensemble.

Intervention Type: OTHER

Control Exercise

Run for 30 minutes followed by walk for 60 minutes in a temperate (gym-like environment) wearing control clothing ensemble.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Male or female, age 18-45
• Females must be premenopausal
• Body mass index 18.5-30.0 kg m-2
• In good health as determined by the Office of Medical Support & Oversight (OMSO) General Medical Clearance
• Performs aerobic exercise at least 2 times per week and capable of running 2 miles in under 16:00 (8 minute mile pace)
• Willing to abstain from exercise and alcoholic beverages for 24 hours before each study visit.
• Willing to abstain from caffeine for 12 hours prior to all study visits.
• Willing to abstain from food for 2 hours prior to all study visits.
• Willing to abstain from nicotine/tobacco for at least 8 hours prior to all study visits.
• Have supervisor approval if permanent party military or a federal employee at U.S. Army Natick Soldier System Center

Exclusion Criteria

• Females who are pregnant or planning to become pregnant during the study
• Taking dietary supplements, prescriptions, or over the counter medication, other than a contraceptive (unless approved by OMSO & PI)
• Abnormal blood count during OMSO medical screening (For example: hemoglobin (Hb) outside of the typical normal values reported by LabCorp in accordance with OMSO (Normal [Hb] Males = 12.6-17.7 g/dL; Females = 11.1-15.9 g/dL) or hematocrit (Hct) outside of the normal ranges (Normal Hct Males = 37.5-51.0%; Females = 34.0-46.6%) levels, presence of abnormal blood chemicals (hemoglobin S or sickle cell traits)
• Any history of pulmonary or cardiovascular disease
• Any history of asthma
• Current or recent respiratory tract or sinus infections (< 1 month prior)
• History of heat intolerance or orthostatic intolerance
• Diagnosed and/or treated for fluid/electrolyte imbalance within the last 30 days
• History of obstructive disease of the gastrointestinal tract including (but not limited to) diverticulosis, diverticulitis and inflammatory bowel disease, peptic ulcer disease, Crohn's disease, ulcerative colitis.
• Scheduled MRI during testing
• Allergies to adhesives (e.g., medical tape).

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

United States Army Research Institute of Environmental Medicine

FED

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Benjamin J Ryan, PhD

Role: PRINCIPAL_INVESTIGATOR

United States Army Research Institute of Environmental Medicine

Locations

US Army Research Institute of Environmental Medicine

Natick, Massachusetts, United States

Countries

United States

Provided Documents

Document Type: Informed Consent Form

View Document

Other Identifiers

23-14

Identifier Type: -

Identifier Source: org_study_id