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Completed

NCT Number: NCT04538144

Cardiovascular Responses to Heat Waves in the Elderly

The purpose of this study is to assess the cardiovascular responses of the elderly to heat wave conditions

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Key information

Conditions

Aging Body Temperature Changes Heat Stress Disorders Hyperthermia Pathological Conditions, Signs and Symptoms Signs and Symptoms Wounds and Injuries

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Institute for Exercise and Environmental Medicine

Dallas, Texas, 75231, United States

About this study

Heat waves are lethal and cause a disproportionate number of deaths in the elderly relative to any other age group. It is important to note that such deaths are primarily cardiovascular, not hyperthermia itself, in origin. Nevertheless, we know relatively little about the effects of aging on cardiovascular function during actual heat wave-like conditions. The central hypothesis of this work is that the elderly exhibit greater cardiovascular stress during heat wave conditions. Aim 1 will test the hypothesis that recognized impairments in thermoregulatory capacity in the elderly will culminate in heightened cardiovascular stress during prolonged exposure to heat wave conditions. Comprehensive cardiovascular and thermal responses in the elderly, relative to younger adults, will be evaluated during exposure to two prolonged heat wave conditions: hot and humid (replicating the 1995 Chicago heat wave) and very hot and dry (replicating the 2018 Los Angeles heat wave). The expected outcome from this body of work will re-shape our understanding of the consequences of aging on cardiovascular function during heat waves

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Healthy male and female individuals
  • 18-35 years or 65+ years of age
  • Free of any underlying moderate to serious medical conditions

Exclusion criteria

  • Known heart disease; other chronic medical conditions requiring regular medical therapy including cancer, diabetes, neurological diseases, uncontrolled hypertension, and uncontrolled hypercholesterolemia.
  • Taking of any medications (such as beta blockers and non-dihydropyridine calcium channel blockers) that have known influences on either cardiac function or sweating responses.
  • Abnormalities detected on routine screening.
  • Individuals who participate in a structured aerobic exercise training program at moderate to high intensities.
  • Current smokers, as well as individuals who regularly smoked within the past 3 years.
  • Body mass index of greater than 30 kg/m^2
  • Pregnant individuals

Treatment and study plan

Hot and Humid Trial

Other

Individuals will be exposed to a simulated heat wave (hot and humid) condition.

Hot and Dry Trial

Other

Individuals will be exposed to a simulated heat wave (hot and dry) condition.

Primary outcomes

  1. Change in Core Body Temperature

    Time frame: Prior to and after the 3-hour simulated heat wave exposure.

    Core body temperature will be measured via a telemetric pill or rectal temperature probe.

  2. Change in Peak Mitral Annular Systolic Velocity (S')

    Time frame: Prior to, during, and after each simulated heat wave exposure; approximately 20 min each

    Change in peak mitral annular systolic velocity was measured by tissue doppler imaging.

Secondary outcomes

  1. Ending Skin Temperature

    Time frame: At the end of the 3-hour simulated heat wave exposure.

    Skin temperature will be measured from small temperature sensitive electrodes attached to the participant's skin.

  2. Ending Heart Rate

    Time frame: At the end of the 3-hour simulated heat wave exposure.

    Heart rate will be measured via ECG electrodes attached to the participant

  3. Ending Mean Arterial Pressure

    Time frame: At the end of the 3-hour simulated heat wave exposure.

    Arterial blood pressure will be measured using a standard arm blood pressure cuff.

  4. Change in Cardiac Output

    Time frame: Prior to and after the 3-hour simulated heat wave exposure.

    Cardiac output (how much blood is ejected from the heart per minute) was measured using echocardiography.

Sponsors and collaborators

Lead sponsor

University of Texas Southwestern Medical Center

Other

Collaborators

  • American Heart Association
  • National Institute on Aging (NIA)

Registry information

Official study title

Heat Waves in the Elderly: Reducing Thermal and Cardiovascular Consequences

Important dates

Study start
2021
Primary completion
2023
Study completion
2023
First posted
Sep 3, 2020
Registry last updated
Oct 23, 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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