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Identification of Critical Thermal Environments for Aged Adults

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT04284397
Recruitment Status : Recruiting
First Posted : February 25, 2020
Last Update Posted : March 1, 2021
Sponsor:
Information provided by (Responsible Party):
W. Larry Kenney, Penn State University

Brief Summary:
This study evaluates critical environmental limits (temperature and humidity) above which older adults are unable to effectively thermoregulate. Participants will exercise in a series of different environmental conditions to identify combinations of temperature and humidity above which age-related physiological changes cause uncompensable heat stress, resulting in increased risk of heat illness.

Condition or disease Intervention/treatment Phase
Aging Drug: Low dose ASA Other: Control Phase 4

Detailed Description:

The earth's climate is warming well above historical averages, and there is an increased frequency, duration, and severity of heat waves. At the same time, the world's population is rapidly aging. Aging is associated with reductions in thermoregulatory capacity due to reductions in sweating and skin blood flow. For this reason, people ≥65 years exhibit exponentially larger increases in morbidity and mortality during heat waves than younger individuals, with the large majority of excess deaths during heat waves occurring in the elderly.

Compounding the physiological effects of primary aging, co-morbidities and common classes of drugs taken by older adults can further compromise their thermoregulatory function. One such class of medications is cyclooxygenase inhibitors, including aspirin (ASA) and other platelet inhibitors. Provocative data published by our lab indicate that platelet inhibitors including ASA increase the rate of heat storage during passive heat stress by ~25%. Following current clinical guidelines, nearly 40% of US adults over the age of 50 engage in an aspirin therapy regiment for the primary or secondary prevention of cardiovascular disease.

Although there is compelling evidence that aging is associated with decreased heat dissipation and elevated risk of heat illness in hot ambient conditions, the significant question remains: In what specific environments does this age disparity begin to occur? The goal of the current study is to identify and model ambient conditions that are unsafe for older adults. A second aim of the study is to determine the effects of the commonly used platelet inhibitor, acetylsalicylic acid (ASA), on age-specific critical environmental limits.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 32 participants
Allocation: N/A
Intervention Model: Crossover Assignment
Intervention Model Description: Two groups of subjects (young, older) participate in twelve experiments; experimental conditions consist of six different combinations of temperature and humidity and are performed at two different exercise intensities. The experiments are conducted in randomized order and are separated by a minimum of three days. A subgroup of older adults will be asked to complete all trials after taking daily low-dose aspirin for seven days, and aspirin will be continued until all trials are complete.
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Identification of Critical Thermal Environments for Aged Adults
Actual Study Start Date : December 30, 2020
Estimated Primary Completion Date : February 28, 2025
Estimated Study Completion Date : February 28, 2025

Resource links provided by the National Library of Medicine

Drug Information available for: Aspirin

Arm Intervention/treatment
Experimental: Critical Temperature 10 Torr (Lighter)
Subjects will perform exercise at ~200W with ambient water vapor pressure set at 10 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Temperature 14 Torr (Lighter)
Subjects will perform exercise at ~200W with ambient water vapor pressure set at 14 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Temperature 18 Torr (Lighter)
Subjects will perform exercise at ~200W with ambient water vapor pressure set at 18 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Temperature 10 Torr (Light)
Subjects will perform exercise at ~300W with ambient water vapor pressure set at 10 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Temperature 14 Torr (Light)
Subjects will perform exercise at ~300W with ambient water vapor pressure set at 14 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Temperature 18 Torr (Light)
Subjects will perform exercise at ~300W with ambient water vapor pressure set at 18 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Vapor Pressure 26 Degrees (Lighter)
Subjects will perform exercise at ~200W with ambient temperature set at 26 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Vapor Pressure 30 Degrees (Lighter)
Subjects will perform exercise at ~200W with ambient temperature set at 30 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Vapor Pressure 34 Degrees (Lighter)
Subjects will perform exercise at ~200W with ambient temperature set at 34 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Vapor Pressure 26 Degrees (Light)
Subjects will perform exercise at ~300W with ambient temperature set at 26 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Vapor Pressure 30 Degrees (Light)
Subjects will perform exercise at ~300W with ambient temperature set at 30 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Vapor Pressure 34 Degrees (Light)
Subjects will perform exercise at ~300W with ambient temperature set at 34 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Other: Control
All participants will be tested with no treatment.

Experimental: Critical Temperature 10 Torr (Lighter) w/ Aspirin
Subjects will perform exercise at ~200W with ambient water vapor pressure set at 10 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin

Experimental: Critical Temperature 14 Torr (Lighter) w/ Aspirin
After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will perform exercise at ~200W with ambient water vapor pressure set at 14 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin

Experimental: Critical Temperature 18 Torr (Lighter) w/ Aspirin
After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will perform exercise at ~200W with ambient water vapor pressure set at 18 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin

Experimental: Critical Temperature 10 Torr (Light) w/ Aspirin
After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will perform exercise at ~300W with ambient water vapor pressure set at 10 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin

Experimental: Critical Temperature 14 Torr (Light) w/ Aspirin
After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will perform exercise at ~300W with ambient water vapor pressure set at 14 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin

Experimental: Critical Temperature 18 Torr (Light) w/ Aspirin
After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will perform exercise at ~300W with ambient water vapor pressure set at 18 Torr. Ambient temperature will increase by 1 degree Celsius every 5 min until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin

Experimental: Critical Vapor Pressure 26 Degrees (Lighter) w/ Aspirin
After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will perform exercise at ~200W with ambient temperature set at 26 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin

Experimental: Critical Vapor Pressure 30 Degrees (Lighter) w/ Aspirin
After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will perform exercise at ~200W with ambient temperature set at 30 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin

Experimental: Critical Vapor Pressure 34 Degrees (Lighter) w/ Aspirin
After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will perform exercise at ~200W with ambient temperature set at 34 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin

Experimental: Critical Vapor Pressure 26 Degrees (Light) w/ Aspirin
After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will perform exercise at ~300W with ambient temperature set at 26 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin

Experimental: Critical Vapor Pressure 30 Degrees (Light) w/ Aspirin
After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will perform exercise at ~300W with ambient temperature set at 30 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin

Experimental: Critical Vapor Pressure 34 Degrees (Light) w/ Aspirin
After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will perform exercise at ~300W with ambient temperature set at 34 degrees Celsius. Ambient water vapor pressure will increase by 1 Torr every 5 minutes until core temperature begins to rise.
Drug: Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
Other Name: Low-dose aspirin




Primary Outcome Measures :
  1. Temperature and humidity limits for maintaining stable core temperature [ Time Frame: Through study completion, an average of 1 year. ]
    Core temperature will be measured throughout exercise. The point at which heat stress becomes uncompensable will be determined for each environmental and exercise condition by assessing the combination of temperature and humidity at which core temperature begins to rise.


Secondary Outcome Measures :
  1. Core temperature [ Time Frame: Continuous throughout visit until completion of exercise; an average of 2 hours. ]
    Core temperature will be monitored throughout each experimental visit

  2. Sweat rate [ Time Frame: Immediately before and immediately after exercise. ]
    Sweat rate will be determined by measuring nude body mass before and after each experimental visit

  3. Skin temperature [ Time Frame: Continuous throughout visit until completion of exercise; an average of 2 hours. ]
    Skin temperature will be monitored throughout each experimental visit



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 85 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Non-obese with body mass index <30
  • HbA1C <5.7%
  • Low density lipoprotein cholesterol <180 mg/dl
  • Between the 20th and 80th percentiles for sex- and age-appropriate VO2max according to the American College of Sports Medicine 10th edition Guidelines for Exercise Testing and Prescription

Exclusion Criteria:

  • Tobacco use
  • Medications that affect thermoregulatory or cardiovascular responses to exercise
  • Any contraindications to low intensity physical activity on the Physical Activity Readiness Questionnaire
  • Any mobility restrictions that interfere with low intensity physical activity
  • Pregnant or planning to become pregnant in the next 12 months
  • Prior diagnosis of cancer, cardiovascular disease, diabetes, or metabolic syndrome
  • Illegal/recreational drug use

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): NCT04284397


Contacts
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Contact: Lacy M Alexander, Ph.D. 8148671781 lma191@psu.edu

Locations
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United States, Pennsylvania
Noll Laboratory Recruiting
University Park, Pennsylvania, United States, 16802
Contact: W. Larry Kenney, Ph.D.    814-863-1672    w7k@psu.edu   
Contact: S. Tony Wolf, Ph.D.    814-863-8557    saw85@psu.edu   
Sponsors and Collaborators
Penn State University
Investigators
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Principal Investigator: W. Larry Kenney, Ph.D. The Pennsylvania State University
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Responsible Party: W. Larry Kenney, Professor, Penn State University
ClinicalTrials.gov Identifier: NCT04284397    
Other Study ID Numbers: Study14062
First Posted: February 25, 2020    Key Record Dates
Last Update Posted: March 1, 2021
Last Verified: February 2021
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: Yes
Keywords provided by W. Larry Kenney, Penn State University:
Aging
Thermoregulation
Heat stress
Additional relevant MeSH terms:
Layout table for MeSH terms
Aspirin
Anti-Inflammatory Agents, Non-Steroidal
Analgesics, Non-Narcotic
Analgesics
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Anti-Inflammatory Agents
Antirheumatic Agents
Fibrinolytic Agents
Fibrin Modulating Agents
Molecular Mechanisms of Pharmacological Action
Platelet Aggregation Inhibitors
Cyclooxygenase Inhibitors
Enzyme Inhibitors
Antipyretics