Cardiovascular Responses to Heat Waves in the Elderly

Aging Clinical Trial

Official title:

Heat Waves in the Elderly: Reducing Thermal and Cardiovascular Consequences

Clinical Trial Details — Status: Active, not recruiting

Administrative data

• NCT number: NCT04538144
• Other study ID #: STU_2019_1759
• Secondary ID: 1R01AG069005-01
• Status: Active, not recruiting
• Start date: January 19, 2021
• Est. completion date: August 31, 2026

Study information

• Verified date: January 2024
• Source: University of Texas Southwestern Medical Center
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

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

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), 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

Recruitment information / eligibility

• Status: Active, not recruiting
• Enrollment: 50
• Est. completion date: August 31, 2026
• Est. primary completion date: August 31, 2026
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years and older

Eligibility

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

Related Conditions & MeSH terms

• Aging
• Hyperthermia

Intervention

Other:
• Simulated heat wave
Individuals will be exposed to thermoneutral climate conditions and two simulated heat wave conditions.

Locations

Country	Name	City	State
United States	Texas Health Presbyterian Hospital Dallas	Dallas	Texas

Sponsors (3)

Lead Sponsor	Collaborator
University of Texas Southwestern Medical Center	American Heart Association, National Institute on Aging (NIA)

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Core body temperature	Core body temperature will be measured from gastrointestinal temperature via an ingestible telemetric pill.	Prior to and throughout each simulated heat wave exposure; an average of 480 minutes.
Primary	Measures of left ventricular function	Measures of left ventricular function, such as ventricular wall motion and ventricular filling, will be obtained from echocardiography images.	Prior to, during, and after each simulated heat wave exposure; approximately 20 min each
Secondary	Skin temperature	Skin temperature will be measured from small temperature sensitive electrodes attached to the participant's skin	Prior to and throughout each simulated heat wave exposure; an average of 480 minutes.
Secondary	Heart rate	Heart rate will be measured from ECG electrodes attached to the participant	Prior to and throughout each simulated heat wave exposure; an average of 480 minutes.
Secondary	Arterial blood pressure	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.
Secondary	Cardiac output	Cardiac output (how much blood is ejected from the heart) will be measured using echocardiography and nitrous oxide rebreathing approaches.	Prior to, during, and after each simulated heat wave exposure; approximately 20 min each
Secondary	Cerebral perfusion	Cerebral perfusion will be measured by doppler ultrasound of the internal carotid and vertebral arteries	Prior to, during, and after each simulated heat wave exposure; approximately 20 min each