Identification of Critical Thermal Environments for Aged Adults
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Low dose ASA, Control.
- Who it may be relevant to
- Registry conditions: Aging. Basic parameters: from 18 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- United States
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Overview
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.
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.
Interventions
- Drug Low dose ASA
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin. - Other Control
All participants will be tested with no treatment.
Primary outcome measures
- Temperature and humidity limits for maintaining stable core temperature [Time frame: Through study completion, an average of 1 year.]
Secondary outcome measures (3)
- Core temperature [Time frame: Continuous throughout visit until completion of exercise; an average of 2 hours.]
- Sweat rate [Time frame: Immediately before and immediately after exercise.]
- Skin temperature [Time frame: Continuous throughout visit until completion of exercise; an average of 2 hours.]
Eligibility criteria
Inclusion criteria
- Adults aged 18 and older (those 40+ years of age must be cleared by collaborating physician)
- All premenopausal women will be eumenorrheic (by survey)
- Asymptomatic and no signs/symptoms of disease according to the American College of Sports Medicine 10th edition Guidelines for Exercise Testing and Prescription
Exclusion criteria
- 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
- History of Chron's disease, diverticulitis, or similar gastrointestinal disease
- Abnormal resting or exercise electrocardiogram (ECG)
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Allocation
- Randomized
- Model
- Single group
- Masking
- Open label
- Primary purpose
- Basic science
Study locations
United States · 1 center
- Noll Laboratory — University Park
Identifiers
NCT: NCT04284397 · Study14062