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OpenTrials
Completed

NCT Number: NCT06349616

Cooling Strategies for Older Adults in the Heat

The earth's climate is warming, and the number of heat waves has increased in recent years. At the same time, the number of adults over the age of 65 is growing. Humans sweat and increase blood flow to the skin to cool their body when they get hot. Older adults do not do this as well as young adults. This makes it harder to safely be in warm and/or humid conditions. It is important to learn about cooling strategies for older adults to safely be in warm and/or humid conditions.

There is compelling evidence that intermittent hand and forearm cold-water immersion effectively reduces the rise of core temperature during heat stress in older adults. However, it is still unknown if this is an effective cooling strategy for older adults. Furthermore, our laboratory has shown that folic acid supplementation improves blood flow responses in older adults. This may be beneficial to older adults during heat stress.

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Key information

Conditions

Aging Heat Stress Disorders Wounds and Injuries

Age range

65 year–100 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Noll Laboratory

University Park, Pennsylvania, 16802, United States

About this study

Subjects sign an informed consent form and undergo a medical screening prior to participation. The screening includes a physical exam, anthropometry, chemical and lipid profiles.

Subjects participate in 4 experimental trials, 2 while on folic acid supplementation and 2 while on placebo. The order of treatment (folic acid supplementation or placebo) is randomized. Participants will place their hands and forearms in cold tap water intermittently for one of the two trials for each treatment. The order of the hand and forearm immersion trial is randomized for each treatment. The trials are separated by at least five days. For each experiment, core temperature, heart rate, blood pressure, skin temperature, and sweat rate are measured. Each experimental visit will last 2 hours.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults aged 65 and older
  • English proficiency

Exclusion criteria

  • Chron's disease, diverticulitis, or similar gastrointestinal disease
  • Abnormal resting exercise electrocardiogram (ECG)
  • Tobacco use
  • High-risk determined by the Atherosclerotic Cardiovascular Disease (CVD) Risk Factor Assessment
  • Antiepileptic or antiseizure medications
  • Methotrexate

Treatment and study plan

Intermittent cold-water hand and forearm immersion

Other

Participants will be seated at rest in a hot and humid environment. At 2 time points in the experiment, participants will place their hands and forearms in a bucket of cold tap water for 10 minutes.

No intermittent cold-water hand and forearm immersion

Other

Participants will be seated at rest in a hot and humid environment.

Primary outcomes

  1. Core temperature

    Time frame: A slope of core temperature for each experimental aim is calculated and reported through study completion, an average of 1 year.

    Core temperature will be monitored throughout each 2 hour experimental visit.

  2. Heart rate

    Time frame: A slope of heart rate for each experimental aim is calculated and reported through study completion, an average of 1 year.

    Heart rate will be monitored continuously throughout each 2 hour experimental visit.

  3. Blood Pressure

    Time frame: Blood pressure for each experimental aim is recorded and reported through study completion, an average of 1 year.

    Blood pressures will be taken every 10 minutes throughout each 2 hour experimental visit.

Secondary outcomes

  1. Body Mass

    Time frame: Baseline immediately before beginning the experimental visit and then once again at the end of the 2 hour experimental visit

    Body weight measured on a scale

  2. Skin Temperature

    Time frame: Mean skin temperature for each experimental aim is calculated and reported through study completion, an average of 1 year

    Average mean skin temperature

Sponsors and collaborators

Lead sponsor

Penn State University

Other

Registry information

Official study title

Acute and Chronic Interventions to Improve Heat Loss During Uncompensable Humid Heat Stress in Older Adults

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Apr 5, 2024
Registry last updated
Jul 24, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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