AgingEarly Phase 1NCT04284397
Identification of Critical Thermal Environments for Aged Adults
A Early Phase 1 study testing Low dose ASA in people with Aging, run by Penn State University at 1 site in United States.
Trial 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… Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Aging
- What is being tested?
- Low dose ASA
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 190 participants
- Where
- 1 siteUnited States
- Study dates
- 30 Dec 2020to 27 Feb 2027
- Phase
- Early Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Noll Laboratory
University Park, Pennsylvania, 16802
W. Larry Kenney, Ph.D., 814-863-1672, w7k@psu.edu
S. Tony Wolf, Ph.D., 814-863-8557, saw85@psu.edu
About this study
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.
Read the 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.
- Conditions
- Aging
- Being tested
- Low dose ASA, Control
- Keywords
- Aging, Thermoregulation, Heat stress
- Medical subject headings
- Heat Stress Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low dose ASADrug
Also called Low-dose aspirin
A sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin.
ControlOther
All participants will be tested with no treatment.
| Study group | Role | What they receive |
|---|---|---|
| Critical Environmental Limits | Experimental | Subjects will perform exercise at ~200-300W with ambient temperature or humidity increasing every 5 min throughout the trial until core temperature begins to rise. Receives: Other: Control |
| Aspirin Supplementation | Experimental | After a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will repeat critical environmental limits trials. As before, subjects will perform exercise at ~200-300W with ambient temperature or humidity increasing every 5 min throughout the trial until core temperature begins to rise. Receives: Drug: Low dose ASA |
What is being measured
The primary outcome is the main question the study is designed to answer.
Temperature and humidity limits for maintaining stable core temperature
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.
Measured: Through study completion, an average of 1 year.
Secondary outcomes (3)
Core temperature
Core temperature will be monitored throughout each experimental visit
Measured: Continuous throughout visit until completion of exercise; an average of 2 hours.
Sweat rate
Sweat rate will be determined by measuring nude body mass before and after each experimental visit
Measured: Immediately before and immediately after exercise.
Skin temperature
Skin temperature will be monitored throughout each experimental visit
Measured: Continuous throughout visit until completion of exercise; an average of 2 hours.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Feb 2020
- Study start30 Dec 2020
- Primary completion27 Feb 2027 (estimated)
- Study completion27 Feb 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for AgingStudies of the same condition, open and under way.
- More trials run by Penn State UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Single group
- 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)
- Enrolment
- 190 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Penn State University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, W. Larry Kenney, Penn State University
- Investigators
- W. Larry Kenney, Ph.D., Principal investigator, The Pennsylvania State University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04284397
- Sponsor's protocol ID
- Study14062
- Status last verified
- Jan 2026
- First submitted
- 20 Feb 2020
- Last updated
- 27 Jan 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 27 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Identification of Critical Thermal Environments for Aged Adults
- ClinicalTrials.gov ID
- NCT04284397
- Acronym / sponsor ID
- Study14062
- Conditions
- Aging
- Keywords
- Aging, Thermoregulation, Heat stress
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 190 participants (estimated)
- Lead sponsor
- Penn State UniversityUniversity, hospital or other
- Study start
- 30 Dec 2020 (actual)
- Primary completion
- 27 Feb 2027 (estimated)
- Study completion
- 27 Feb 2027 (estimated)
- First posted
- 25 Feb 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 2
- 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.
| Arm | Type | Receives |
|---|---|---|
| Critical Environmental Limits | Experimental | Other: ControlSubjects will perform exercise at ~200-300W with ambient temperature or humidity increasing every 5 min throughout the trial until core temperature begins to rise. |
| Aspirin Supplementation | Experimental | Drug: Low dose ASAAfter a minimum of 7 days of daily, low-dose aspirin ingestion, older subjects will repeat critical environmental limits trials. As before, subjects will perform exercise at ~200-300W with ambient temperature or humidity increasing every 5 min throughout the trial until core temperature begins to rise. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- 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
Key exclusion criteria (8 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Low dose ASAAlso: Low-dose aspirinA sub-group of older adults will be re-tested after 7 days of treatment with low-dose aspirin. | Drug | Aspirin Supplementation |
| ControlAll participants will be tested with no treatment. | Other | Critical Environmental Limits |
Primary outcome
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.
3 secondary outcomes
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.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Jan 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
W. Larry Kenney, Ph.D. principal investigator
The Pennsylvania State University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Low dose ASA in people with Aging, run by Penn State University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 27 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Lacy M Alexander, Ph.D. (8148671781, lma191@psu.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Temperature and humidity limits for maintaining stable core temperature (time frame: Through study completion, an average of 1 year.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Jan 2026.