Clinical trial NCT04538144: Cardiovascular Responses to Heat Waves in the Elderly
Official title: Heat Waves in the Elderly: Reducing Thermal and Cardiovascular Consequences
Study type: OBSERVATIONAL
Overall status: ACTIVE_NOT_RECRUITING
Conditions: Aging
Hyperthermia
Keywords: aging
heat wave
cardiovascular
Lead sponsor: University of Texas Southwestern Medical Center
Sponsor class: OTHER
Collaborators: name: American Heart Association
name: National Institute on Aging (NIA)
First posted: 2020-09-03
Enrollment: 50
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: The study population will be healthy younger and older individuals identified from the general population.

Brief summary: 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), 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

Eligibility criteria: 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

Primary outcomes:
measure: Core body temperature
timeFrame: Prior to and throughout each simulated heat wave exposure; an average of 480 minutes.
measure: Measures of left ventricular function
timeFrame: Prior to, during, and after each simulated heat wave exposure; approximately 20 min each
Secondary outcomes:
measure: Skin temperature
timeFrame: Prior to and throughout each simulated heat wave exposure; an average of 480 minutes.
measure: Heart rate
timeFrame: Prior to and throughout each simulated heat wave exposure; an average of 480 minutes.
measure: Arterial blood pressure
timeFrame: Prior to and throughout each simulated heat wave exposure; an average of 480 minutes.
measure: Cardiac output
timeFrame: Prior to, during, and after each simulated heat wave exposure; approximately 20 min each
measure: Cerebral perfusion
timeFrame: Prior to, during, and after each simulated heat wave exposure; approximately 20 min each
Other outcomes:
Locations:
city: Dallas
country: United States
facility: Texas Health Presbyterian Hospital Dallas
state: Texas
Study officials:
References: