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Cardiovascular Responses to Heat Waves in the Elderly

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ClinicalTrials.gov Identifier: NCT04538144
Recruitment Status : Recruiting
First Posted : September 3, 2020
Last Update Posted : February 4, 2021
Sponsor:
Information provided by (Responsible Party):
Craig Crandall, University of Texas Southwestern Medical Center

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

Condition or disease Intervention/treatment
Aging Hyperthermia Other: Simulated heat wave

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

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Study Type : Observational
Estimated Enrollment : 50 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Heat Waves in the Elderly: Reducing Thermal and Cardiovascular Consequences
Actual Study Start Date : January 19, 2021
Estimated Primary Completion Date : August 31, 2022
Estimated Study Completion Date : August 31, 2024

Group/Cohort Intervention/treatment
Younger participants
Individuals aged 18-39 years
Other: Simulated heat wave
Individuals will be exposed to thermoneutral climate conditions and two simulated heat wave conditions.

Older participants
Individuals aged 65 years or older
Other: Simulated heat wave
Individuals will be exposed to thermoneutral climate conditions and two simulated heat wave conditions.




Primary Outcome Measures :
  1. Core body temperature [ Time Frame: Prior to and throughout each simulated heat wave exposure; an average of 480 minutes. ]
    Core body temperature will be measured from gastrointestinal temperature via an ingestible telemetric pill.

  2. Measures of left ventricular function [ Time Frame: Prior to, during, and after each simulated heat wave exposure; approximately 20 min each ]
    Measures of left ventricular function, such as ventricular wall motion and ventricular filling, will be obtained from echocardiography images.


Secondary Outcome Measures :
  1. Skin temperature [ Time Frame: Prior to and throughout each simulated heat wave exposure; an average of 480 minutes. ]
    Skin temperature will be measured from small temperature sensitive electrodes attached to the participant's skin

  2. Heart rate [ Time Frame: Prior to and throughout each simulated heat wave exposure; an average of 480 minutes. ]
    Heart rate will be measured from ECG electrodes attached to the participant

  3. 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

  4. Cardiac output [ Time Frame: Prior to, during, and after each simulated heat wave exposure; approximately 20 min each ]
    Cardiac output (how much blood is ejected from the heart) will be measured using echocardiography and nitrous oxide rebreathing approaches.

  5. Cerebral perfusion [ Time Frame: Prior to, during, and after each simulated heat wave exposure; approximately 20 min each ]
    Cerebral perfusion will be measured by doppler ultrasound of the internal carotid and vertebral arteries



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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
The study population will be healthy younger and older individuals identified from the general population.
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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04538144


Contacts
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Contact: Luke Belval, PhD 214-345-6503 LukeBelval@texashealth.org
Contact: Amy Slack-Bryant 214-345-8740 amybryant@texashealth.org

Locations
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United States, Texas
Texas Health Presbyterian Hospital Dallas Recruiting
Dallas, Texas, United States, 75231
Contact: Luke Belval, PhD    214-345-6503    lukebelval@texashealth.org   
Contact: Ileana Hill, BS RN    214-345-6502    ileanahill@texashealth.org   
Principal Investigator: Craig Crandall, Ph.D.         
Sponsors and Collaborators
University of Texas Southwestern Medical Center
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Responsible Party: Craig Crandall, Professor of Medicine, University of Texas Southwestern Medical Center
ClinicalTrials.gov Identifier: NCT04538144    
Other Study ID Numbers: STU_2019_1759
First Posted: September 3, 2020    Key Record Dates
Last Update Posted: February 4, 2021
Last Verified: February 2021

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Craig Crandall, University of Texas Southwestern Medical Center:
aging
heat wave
cardiovascular
Additional relevant MeSH terms:
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Fever
Body Temperature Changes