Acute and Chronic Interventions to Improve Heat Loss During Uncompensable Humid Heat Stress in Older Adults
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Penn State University
- Enrollment
- 12
- Locations
- 1
- Primary Endpoint
- Blood Pressure
Study Overview
Brief Summary
The earth's climate is warming, and the number of heat waves has increased in recent years. At the same time, the number of adults over the age of 65 is growing. Humans sweat and increase blood flow to the skin to cool their body when they get hot. Older adults do not do this as well as young adults. This makes it harder to safely be in warm and/or humid conditions. It is important to learn about cooling strategies for older adults to safely be in warm and/or humid conditions.
There is compelling evidence that intermittent hand and forearm cold-water immersion effectively reduces the rise of core temperature during heat stress in older adults. However, it is still unknown if this is an effective cooling strategy for older adults. Furthermore, our laboratory has shown that folic acid supplementation improves blood flow responses in older adults. This may be beneficial to older adults during heat stress.
Detailed Description
Subjects sign an informed consent form and undergo a medical screening prior to participation. The screening includes a physical exam, anthropometry, chemical and lipid profiles.
Subjects participate in 4 experimental trials, 2 while on folic acid supplementation and 2 while on placebo. The order of treatment (folic acid supplementation or placebo) is randomized. Participants will place their hands and forearms in cold tap water intermittently for one of the two trials for each treatment. The order of the hand and forearm immersion trial is randomized for each treatment. The trials are separated by at least five days. For each experiment, core temperature, heart rate, blood pressure, skin temperature, and sweat rate are measured. Each experimental visit will last 2 hours.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Basic Science
- Masking
- Double (Participant, Investigator)
Eligibility Criteria
- Ages
- 65 Years to 100 Years (Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Adults aged 65 and older
- •English proficiency
Exclusion Criteria
- •Chron's disease, diverticulitis, or similar gastrointestinal disease
- •Abnormal resting exercise electrocardiogram (ECG)
- •Tobacco use
- •High-risk determined by the Atherosclerotic Cardiovascular Disease (CVD) Risk Factor Assessment
- •Antiepileptic or antiseizure medications
- •Methotrexate
Arms & Interventions
Folic acid supplementation
5 mg/day folic acid for 6-7 weeks
Intervention: Intermittent cold-water hand and forearm immersion (Other)
Folic acid supplementation
5 mg/day folic acid for 6-7 weeks
Intervention: No intermittent cold-water hand and forearm immersion (Other)
Control
Cellulose placebo tablet for 6-7 weeks
Intervention: Intermittent cold-water hand and forearm immersion (Other)
Control
Cellulose placebo tablet for 6-7 weeks
Intervention: No intermittent cold-water hand and forearm immersion (Other)
Outcomes
Primary Outcomes
Blood Pressure
Time Frame: Blood pressure for each experimental aim is recorded and reported through study completion, an average of 1 year.
Blood pressures will be taken every 10 minutes throughout each 2 hour experimental visit.
Core temperature
Time Frame: A slope of core temperature for each experimental aim is calculated and reported through study completion, an average of 1 year.
Core temperature will be monitored throughout each 2 hour experimental visit.
Heart rate
Time Frame: A slope of heart rate for each experimental aim is calculated and reported through study completion, an average of 1 year.
Heart rate will be monitored continuously throughout each 2 hour experimental visit.
Secondary Outcomes
- Body Mass(Baseline immediately before beginning the experimental visit and then once again at the end of the 2 hour experimental visit)
- Skin Temperature(Mean skin temperature for each experimental aim is calculated and reported through study completion, an average of 1 year)
Investigators
W. Larry Kenney
Professor of Kinesiology and Physiology
Penn State University