Cardiovascular Responses to Heat Waves in the Elderly

October 21, 2025 updated by: Craig Crandall, University of Texas Southwestern Medical Center

Heat Waves in the Elderly: Reducing Thermal and Cardiovascular Consequences

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

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

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

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
59

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Texas
      • Dallas, Texas, United States, 75231
        • Institute for Exercise and Environmental Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Study Population

The study population will be healthy younger and older individuals identified from the general population.

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Other: Younger participants: Hot/Dry then Hot/Humid
Individuals aged 18-39 years who completed the hot/dry trial first and the hot/humid trial second.
Other: Hot and Humid Trial
Individuals will be exposed to a simulated heat wave (hot and humid) condition.
Other: Hot and Dry Trial
Individuals will be exposed to a simulated heat wave (hot and dry) condition.
Other: Older participants: Hot/Dry then Hot/Humid
Individuals aged 65 years or older who completed the hot/dry trial first and the hot/humid trial second.
Other: Hot and Humid Trial
Individuals will be exposed to a simulated heat wave (hot and humid) condition.
Other: Hot and Dry Trial
Individuals will be exposed to a simulated heat wave (hot and dry) condition.
Other: Younger participants: Hot/Humid then Hot/Dry
Individuals aged 18-39 years who completed the hot/humid trial first and the hot/dry trial second.
Other: Hot and Humid Trial
Individuals will be exposed to a simulated heat wave (hot and humid) condition.
Other: Hot and Dry Trial
Individuals will be exposed to a simulated heat wave (hot and dry) condition.
Other: Older participants: Hot/Humid then Hot/Dry
Individuals aged 65 years or older who completed the hot/humid trial first and the hot/dry trial second.
Other: Hot and Humid Trial
Individuals will be exposed to a simulated heat wave (hot and humid) condition.
Other: Hot and Dry Trial
Individuals will be exposed to a simulated heat wave (hot and dry) condition.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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.
Prior to and after the 3-hour simulated heat wave exposure.
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.
Prior to, during, and after each simulated heat wave exposure; approximately 20 min each

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
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.
At the end of the 3-hour simulated heat wave exposure.
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
At the end of the 3-hour simulated heat wave exposure.
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.
At the end of the 3-hour simulated heat wave exposure.
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.
Prior to and after the 3-hour simulated heat wave exposure.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Texas Southwestern Medical Center

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute on Aging (NIA)
American Heart Association

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 19, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 20, 2023

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 20, 2023

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 28, 2020

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 2, 2020

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 3, 2020

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
October 23, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 21, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • STU_2019_1759
  • 1R01AG069005-01 (U.S. NIH Grant/Contract)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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