Impact of Extreme Heat on Myocardial Blood Flow and Flow Reserve in Young and Older Adults

Description

Extreme heat causes a disproportionate number of hospitalizations and deaths in older adults relative to any other age group. Importantly, many hospitalizations and deaths are primarily due to cardiovascular events such as myocardial infarction. Previous data indicate that older adults have attenuated skin blood flow and sweating responses when exposed to heat, resulting greater increase in core body temperature. Despite these observations, relatively little is known about the risk for myocardial ischemia potentially contributing to the aforementioned higher morbidity and mortality in older adults during heat waves. The broad objective of this work is to determine the impact of ambient heat exposure on myocardial blood flow and flow reserve in young and older adults. Aim 1 will test the hypothesis that older adults exhibit attenuated myocardial flow reserve compared to young adults during heat stress. Aim 2 will determine if the percent of maximal myocardial flow reserve (assess via vasodilator stress) during heat exposure is higher in older adults compared to young adults. The expected outcome from this body of work will improve our understanding of the consequences of aging on cardiovascular responses to ambient heat stress.

Conditions

Aging, Heat Stress, Hyperthermia, Heat Strain

Study Overview

Study Details

Study overview

Extreme heat causes a disproportionate number of hospitalizations and deaths in older adults relative to any other age group. Importantly, many hospitalizations and deaths are primarily due to cardiovascular events such as myocardial infarction. Previous data indicate that older adults have attenuated skin blood flow and sweating responses when exposed to heat, resulting greater increase in core body temperature. Despite these observations, relatively little is known about the risk for myocardial ischemia potentially contributing to the aforementioned higher morbidity and mortality in older adults during heat waves. The broad objective of this work is to determine the impact of ambient heat exposure on myocardial blood flow and flow reserve in young and older adults. Aim 1 will test the hypothesis that older adults exhibit attenuated myocardial flow reserve compared to young adults during heat stress. Aim 2 will determine if the percent of maximal myocardial flow reserve (assess via vasodilator stress) during heat exposure is higher in older adults compared to young adults. The expected outcome from this body of work will improve our understanding of the consequences of aging on cardiovascular responses to ambient heat stress.

Impact of Extreme Heat on Myocardial Blood Flow and Flow Reserve in Young and Older Adults

Impact of Extreme Heat on Myocardial Blood Flow and Flow Reserve in Young and Older Adults

Condition
Aging
Intervention / Treatment

-

Contacts and Locations

Dallas

Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States, 75231

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.

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Eligibility Criteria

  • * Healthy male and female individuals
  • * 18-35 years or 65+ years of age
  • * Free of any underlying moderate to serious medical conditions
  • * 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.
  • * 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

Ages Eligible for Study

18 Years to

Sexes Eligible for Study

ALL

Accepts Healthy Volunteers

Yes

Collaborators and Investigators

University of Texas Southwestern Medical Center,

Study Record Dates

2027-02-01