Identification of Critical Thermal Environments for Aged Adults

NCT04284397 | Recruiting Early Phase 1 DMC FDA Drug

• 1 other identifier: Study14062
• Study Type: interventional
• Target: 190
• Locations: 1 country
• Sites: 1

Brief Summary

This study evaluates critical environmental limits (temperature and humidity) above which older adults are unable to effectively thermoregulate. Participants will exercise in a series of different environmental conditions to identify combinations of temperature and humidity above which age-related physiological changes cause uncompensable heat stress, resulting in increased risk of heat illness.

Conditions

Aging

Keywords

Aging; Thermoregulation; Heat stress

Outcome Measures

Primary Outcomes (1)

• Temperature and humidity limits for maintaining stable core temperature

  Core temperature will be measured throughout exercise. The point at which heat stress becomes uncompensable will be determined for each environmental and exercise condition by assessing the combination of temperature and humidity at which core temperature begins to rise.

  Through study completion, an average of 1 year.

Secondary Outcomes (3)

• Core temperature

  Continuous throughout visit until completion of exercise; an average of 2 hours.

• Sweat rate

  Immediately before and immediately after exercise.

• Skin temperature

  Continuous throughout visit until completion of exercise; an average of 2 hours.

Study Arms (2)

Critical Environmental Limits

EXPERIMENTAL

Subjects will perform exercise at \~200-300W with ambient temperature or humidity increasing every 5 min throughout the trial until core temperature begins to rise.

Other: Control

Aspirin Supplementation

EXPERIMENTAL

After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will repeat critical environmental limits trials. As before, subjects will perform exercise at \~200-300W with ambient temperature or humidity increasing every 5 min throughout the trial until core temperature begins to rise.

Drug: Low dose ASA

Interventions

Control OTHER

All participants will be tested with no treatment.

Critical Environmental Limits

Low dose ASA DRUG

A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.

Also known as: Low-dose aspirin

Aspirin Supplementation

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults aged 18 and older (those 40+ years of age must be cleared by collaborating physician)
• All premenopausal women will be eumenorrheic (by survey)
• Asymptomatic and no signs/symptoms of disease according to the American College of Sports Medicine 10th edition Guidelines for Exercise Testing and Prescription

You may not qualify if:

• Medications that affect thermoregulatory or cardiovascular responses to exercise
• Any contraindications to low intensity physical activity on the Physical Activity Readiness Questionnaire
• Any mobility restrictions that interfere with low intensity physical activity
• Pregnant or planning to become pregnant in the next 12 months
• Prior diagnosis of cancer, cardiovascular disease, diabetes, or metabolic syndrome
• Illegal/recreational drug use
• History of Chron's disease, diverticulitis, or similar gastrointestinal disease
• Abnormal resting or exercise electrocardiogram (ECG)

Sponsors & Collaborators

• Penn State University: lead

Study Sites (1)

Noll Laboratory

University Park, Pennsylvania, 16802, United States

RECRUITING

MeSH Terms

Conditions

Heat Stress Disorders

Interventions

Aspirin

Condition Hierarchy (Ancestors)

Wounds and Injuries

Intervention Hierarchy (Ancestors)

Salicylates; Hydroxybenzoates; Phenols; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons; Organic Chemicals

Study Officials

• W. Larry Kenney, Ph.D.

  The Pennsylvania State University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Lacy M Alexander, Ph.D.

CONTACT

8148671781; lma191@psu.edu

Study Design

• Study Type: interventional
• Phase: early phase 1
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: Two groups of subjects (young, older) participate in twelve experiments; experimental conditions consist of six different combinations of temperature and humidity and are performed at two different exercise intensities. The experiments are conducted in randomized order and are separated by a minimum of three days. A subgroup of older adults will be asked to complete all trials after taking daily low-dose aspirin for seven days, and aspirin will be continued until all trials are complete.

Study Record Dates

• First Submitted: February 20, 2020
• First Posted: February 25, 2020
• Study Start: December 30, 2020
• Primary Completion (Estimated): February 27, 2027
• Study Completion (Estimated): February 27, 2027
• Last Updated: January 27, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)