AgingNCT04538144
Cardiovascular Responses to Heat Waves in the Elderly
A study testing Hot and Humid Trial and Hot and Dry Trial in people with Aging and Hyperthermia, run by University of Texas Southwestern Medical Center at 1 site in United States.
Trial summary
The purpose of this study is to assess the cardiovascular responses of the elderly to heat wave conditions Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Aging, Hyperthermia
- What is being tested?
- Hot and Humid Trial and Hot and Dry Trial
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 59 participants
- Where
- 1 siteUnited States
- Study dates
- 19 Jan 2021to 20 Feb 2023
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy male and female individuals
- 18-35 years or 65+ years of age
- Free of any underlying moderate to serious medical conditions
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
United States1 site
Institute for Exercise and Environmental Medicine
Dallas, Texas, 75231
About this study
Official title: 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
Read the 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
- Conditions
- Aging, Hyperthermia
- Being tested
- Hot and Humid Trial, Hot and Dry Trial
- Keywords
- aging, heat wave, cardiovascular
- Medical subject headings
- Hyperthermia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Hot and Humid TrialOther
Individuals will be exposed to a simulated heat wave (hot and humid) condition.
Hot and Dry TrialOther
Individuals will be exposed to a simulated heat wave (hot and dry) condition.
| Study group | Role | What they receive |
|---|---|---|
| Younger participants: Hot/Dry then Hot/Humid | Other | Individuals aged 18-39 years who completed the hot/dry trial first and the hot/humid trial second. Receives: Other: Hot and Humid Trial; Other: Hot and Dry Trial |
| Older participants: Hot/Dry then Hot/Humid | Other | Individuals aged 65 years or older who completed the hot/dry trial first and the hot/humid trial second. Receives: Other: Hot and Humid Trial; Other: Hot and Dry Trial |
| Younger participants: Hot/Humid then Hot/Dry | Other | Individuals aged 18-39 years who completed the hot/humid trial first and the hot/dry trial second. Receives: Other: Hot and Humid Trial; Other: Hot and Dry Trial |
| Older participants: Hot/Humid then Hot/Dry | Other | Individuals aged 65 years or older who completed the hot/humid trial first and the hot/dry trial second. Receives: Other: Hot and Humid Trial; Other: Hot and Dry Trial |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Core Body Temperature
Core body temperature will be measured via a telemetric pill or rectal temperature probe.
Measured: Prior to and after the 3-hour simulated heat wave exposure.
Change in Peak Mitral Annular Systolic Velocity (S')
Change in peak mitral annular systolic velocity was measured by tissue doppler imaging.
Measured: Prior to, during, and after each simulated heat wave exposure; approximately 20 min each
Secondary outcomes (4)
Ending Skin Temperature
Skin temperature will be measured from small temperature sensitive electrodes attached to the participant's skin.
Measured: At the end of the 3-hour simulated heat wave exposure.
Ending Heart Rate
Heart rate will be measured via ECG electrodes attached to the participant
Measured: At the end of the 3-hour simulated heat wave exposure.
Ending Mean Arterial Pressure
Arterial blood pressure will be measured using a standard arm blood pressure cuff.
Measured: At the end of the 3-hour simulated heat wave exposure.
Change in Cardiac Output
Cardiac output (how much blood is ejected from the heart per minute) was measured using echocardiography.
Measured: Prior to and after the 3-hour simulated heat wave exposure.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Sep 2020
- Study start19 Jan 2021
- Primary completion20 Feb 2023
- Study completion20 Feb 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for AgingStudies of the same condition, open and under way.
- More trials run by University of Texas Southwestern Medical CenterThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 59 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Texas Southwestern Medical Center
- Sponsor type
- University, hospital or other
- Collaborators
- American Heart Association, National Institute on Aging (NIA)
- Responsible party
- Principal investigator, Craig Crandall, University of Texas Southwestern Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04538144
- Sponsor's protocol ID
- STU_2019_1759
- Other IDs
- 1R01AG069005-01
- Status last verified
- Oct 2025
- First submitted
- 28 Aug 2020
- Last updated
- 23 Oct 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 23 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Heat Waves in the Elderly: Reducing Thermal and Cardiovascular Consequences
- ClinicalTrials.gov ID
- NCT04538144
- Acronym / sponsor ID
- STU_2019_1759
- Conditions
- Aging, Hyperthermia
- Keywords
- aging, heat wave, cardiovascular
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 59 participants (actual)
- Lead sponsor
- University of Texas Southwestern Medical CenterUniversity, hospital or other
- Collaborators
- American Heart Association, National Institute on Aging (NIA)
- Study start
- 19 Jan 2021 (actual)
- Primary completion
- 20 Feb 2023 (actual)
- Study completion
- 20 Feb 2023 (actual)
- First posted
- 3 Sep 2020 (actual)
- Results
- Posted 7 Aug 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to assess the cardiovascular responses of the elderly to heat wave conditions
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 design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Younger participants: Hot/Dry then Hot/Humid | Other | Other: Hot and Humid Trial, Other: Hot and Dry TrialIndividuals aged 18-39 years who completed the hot/dry trial first and the hot/humid trial second. |
| Older participants: Hot/Dry then Hot/Humid | Other | Other: Hot and Humid Trial, Other: Hot and Dry TrialIndividuals aged 65 years or older who completed the hot/dry trial first and the hot/humid trial second. |
| Younger participants: Hot/Humid then Hot/Dry | Other | Other: Hot and Humid Trial, Other: Hot and Dry TrialIndividuals aged 18-39 years who completed the hot/humid trial first and the hot/dry trial second. |
| Older participants: Hot/Humid then Hot/Dry | Other | Other: Hot and Humid Trial, Other: Hot and Dry TrialIndividuals aged 65 years or older who completed the hot/humid trial first and the hot/dry trial second. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Healthy male and female individuals
- 18-35 years or 65+ years of age
- Free of any underlying moderate to serious medical conditions
Key exclusion criteria (7 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Hot and Humid TrialIndividuals will be exposed to a simulated heat wave (hot and humid) condition. | Other | Older participants: Hot/Dry then Hot/Humid, Older participants: Hot/Humid then Hot/Dry, Younger participants: Hot/Dry then Hot/Humid, Younger participants: Hot/Humid then Hot/Dry |
| Hot and Dry TrialIndividuals will be exposed to a simulated heat wave (hot and dry) condition. | Other | Older participants: Hot/Dry then Hot/Humid, Older participants: Hot/Humid then Hot/Dry, Younger participants: Hot/Dry then Hot/Humid, Younger participants: Hot/Humid then Hot/Dry |
Primary outcome
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.
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.
4 secondary outcomes
Ending Skin Temperature
Time frame: 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.
Ending Mean Arterial Pressure
Time frame: 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.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Oct 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Hot and Humid Trial and Hot and Dry Trial in people with Aging and Hyperthermia, run by University of Texas Southwestern Medical Center at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 23 Oct 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 7 Aug 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Core Body Temperature (time frame: Prior to and after the 3-hour simulated heat wave exposure.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Oct 2025.