Heat Waves and the Elderly - Cooling Modalities

September 2, 2026 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 how well cooling modalities work in reducing cardiovascular stress of the elderly to heat wave conditions

Study Overview

Status

Status

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

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. Such deaths are primarily cardiovascular, not hyperthermia itself, in origin. The central hypothesis of this work is that cardiovascular stress during heat wave conditions in the elderly can be reduced by applying low-energy cooling modalities. Comprehensive cardiovascular and thermal responses in the elderly will be evaluated during exposure to two prolonged heat wave conditions: hot and humid (replicating the 1995 Chicago heat wave), very hot and dry (replicating the 2018 Los Angeles heat wave). With each of these heat wave conditions individuals will be exposed to the following cooling modalities: no cooling (control), water spray, fan use, and fan use plus water spray.

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 (Estimated)

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.
100

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

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

65 years and older (Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • 65 years of age or older
  • Free of any significant underlying medical problems based upon a detailed medical history and physical exam

Exclusion Criteria:

  • Known heart disease
  • Other chronic medical conditions requiring regular medical therapy including cancer, diabetes, uncontrolled hypertension, and uncontrolled hypercholesterolemia etc;
  • Abnormality detected on routine screening suggestive of provokable ischemia or previously undetected cardiac disease or resting left bundle branch block on screening electrocardiogram.
  • Current smokers, as well as individuals who regularly smoked within the past 3 years
  • Subject with a body mass index ≥31 kg/m2
  • 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: Prevention
  • Allocation: 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.
Experimental: Very hot and dry
Subjects will be exposed to 3 hours in a climate chamber set to approximately 47 deg C and 15% relative humidity, which reflects a very hot and dry heat wave condition similar to the 2018 Los Angeles heat wave. Four visits will be required to complete this arm, with each visit a different cooling modality applied.
Other: Water Spray
Participants will receive water spraying on their body throughout the climate chamber exposure.
Other: Fan
Participants will be exposed to a fan throughout the climate chamber exposure.
Other: Water Spray and Fan
Participants will receive both water spraying and a fan throughout the climate chamber exposure.
Other: Control
Participants will NOT receive either water spray or a fan exposure.
Experimental: Hot and humid
Subjects will be exposed to 3 hours in a climate chamber set to approximately 41 deg C and 40% relative humidity, which reflects hot and humid heat wave similar to the 1995 Chicago heat wave. Four visits will be required to complete this arm, with each visit a different cooling modality applied.
Other: Water Spray
Participants will receive water spraying on their body throughout the climate chamber exposure.
Other: Fan
Participants will be exposed to a fan throughout the climate chamber exposure.
Other: Water Spray and Fan
Participants will receive both water spraying and a fan throughout the climate chamber exposure.
Other: Control
Participants will NOT receive either water spray or a fan exposure.

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: Body core temperature will be obtained within 60 min before the heat wave exposure after the 3 hour heat wave exposure.
Change in core body temperature will be measured either from a temperature sensor pill or from a rectal thermometer
Body core temperature will be obtained within 60 min before the heat wave exposure after the 3 hour heat wave exposure.
Change in left ventricular function
Time Frame: Within 60 minutes before each simulated heat wave exposure, around minute 90 of the heat wave exposure, and at the end of the 3 hour heat wave exposure
Measures of left ventricular function, such as ventricular wall motion and ventricular filling, will be obtained from echocardiography images.
Within 60 minutes before each simulated heat wave exposure, around minute 90 of the heat wave exposure, and at the end of the 3 hour heat wave exposure

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
Heart rate
Time Frame: Prior to and throughout each simulated heat wave exposure; approximately 420 minutes
Heart rate will be measured from ECG electrodes attached to the participant
Prior to and throughout each simulated heat wave exposure; approximately 420 minutes
Cardiac output
Time Frame: Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)
Cardiac output (how much blood is ejected from the heart) will be measured using 3D echocardiography.
Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)
Arterial blood pressure
Time Frame: Prior to and throughout each simulated heat wave exposure; an average of 480 minutes
Arterial blood pressure will be measured using a standard arm blood pressure cuff.
Prior to and throughout each simulated heat wave exposure; an average of 480 minutes
Whole body sweat rate
Time Frame: Within 60 minutes before each simulated heat wave exposure and within 30 minutes after each heat wave exposure.
Whole body sweat rate will be measured by through nude weight of the participant.
Within 60 minutes before each simulated heat wave exposure and within 30 minutes after each heat wave exposure.
Markers of renal function and injury - Cystatin C
Time Frame: Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
Markers of renal function and injury (e.g., cystatin C) will be evaluated from blood sampling collection.
Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
Markers of renal function and injury - Creatinine Clearance
Time Frame: Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
Markers of renal function and injury (e.g., creatinine clearance) will be evaluated from blood sampling and urine collection.
Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
Markers of renal function and injury - Insulin-like growth factor-binding protein 7
Time Frame: Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
Markers of renal function and injury (e.g., Insulin-like growth factor-binding protein 7) will be evaluated from urine sampling.
Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
Markers of renal function and injury - Tissue inhibitor of metalloproteinases 2
Time Frame: Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
Markers of renal function and injury (e.g., Tissue inhibitor of metalloproteinases 2) will be evaluated from urine sampling.
Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
Cerebral perfusion
Time Frame: Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)
Cerebral perfusion will be measured by Doppler ultrasound of the internal carotid and vertebral arteries.
Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)
High sensitive cardiac troponin
Time Frame: Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
A plasma-based marker of cardiac stress (high sensitive cardiac troponin) be evaluated from blood sampling.
Within 60 minutes before each simulated heat wave exposure, during each simulated heat wave exposure (up to 3 hours), and within 2 hours after the simulated heat wave exposure
Skin temperature
Time Frame: Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)
Skin temperature will be measured from small temperature sensitive electrodes attached to the participant's skin
Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)
Forced vital capacity (FVC)
Time Frame: Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)
Forced vital capacity will be obtained from spirometry
Within 60 minutes before each simulated heat wave exposure and during each simulated heat wave exposure (up to 3 hours)

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

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.
February 21, 2023

Primary Completion (Estimated)

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.
January 31, 2027

Study Completion (Estimated)

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.
August 31, 2027

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).
July 27, 2022

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.
July 29, 2022

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.
August 2, 2022

Study Record Updates

Last Update Posted (Actual)

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.
September 8, 2026

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.
September 2, 2026

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.
September 1, 2026

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-2022-0625

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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