Limits of surviving extreme heat in older women
Identifying the Upper Environmental Limits of Thermal Compensation in Older Human Females Using a Rapid Humidity Ramp Protocol
This project will test how much hot, humid conditions women aged 65 and older can safely tolerate before their bodies stop being able to cool down.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 12 (estimated) |
| Ages | 65 Years to 85 Years |
| Sex | Female |
| Sponsor | University of Ottawa Academic / other |
| Locations | 2 sites (Ottawa, Ontario and 1 other locations) |
| Trial ID | NCT07032493 on ClinicalTrials.gov |
What this trial studies
This interventional protocol exposes older female participants to controlled hot and humid conditions using a humidity‑ramp protocol and several fixed-condition exposures to identify the point at which heat loss can no longer match heat gain (uncompensable heat stress). Investigators will continuously monitor core and skin temperatures, sweating rate, skin blood flow, and cardiovascular responses to determine compensability limits. Eligible participants include non-smoking older women able to consent, with or without controlled hypertension or type 2 diabetes of at least five years' duration, while safety exclusions remove people with uncontrolled hypertension, serious diabetic complications, or conditions limiting activity. Exposures will be conducted in a laboratory at the University of Ottawa with pre-specified safety stop criteria to protect participants.
Who should consider this trial
Good fit: Ideal candidates are non-smoking women aged 65 or older who can communicate in English or French, provide informed consent, and may have controlled hypertension or type 2 diabetes of at least five years without severe complications.
Not a fit: People with uncontrolled hypertension, severe diabetic complications or autonomic neuropathy, major mobility or cardiorespiratory limitations, or younger men and women outside the target age group are unlikely to benefit from this protocol.
Why it matters
Potential benefit: If successful, the results could define temperature and humidity limits that improve public-health guidance and protect older women during heat waves.
How similar studies have performed: Previous lab studies have documented sex differences in sweating and skin blood flow, but few trials have tested uncompensable heat limits specifically in older women, so the approach is partly supported by prior work yet addresses a novel gap.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * Non-smoking. * English or French speaking. * Ability to provide informed consent. * With or without a) chronic hypertension (elevated resting blood pressure; as defined by Heart and Stroke Canada and Hypertension Canada), b) type 2 diabetes as defined by Diabetes Canada, with at least 5 years having elapsed since time of diagnosis Exclusion Criteria: * Episode(s) of severe hypoglycemia (requiring the assistance of another person) within the previous year, or inability to sense hypoglycemia (hypoglycemia unawareness). * Serious complications related to diabetes (gastroparesis, renal disease, uncontrolled hypertension, severe autonomic neuropathy). * Uncontrolled hypertension - BP \>150 mmHg systolic or \>95 mmHg diastolic in a sitting position. * Restrictions in physical activity due to disease (e.g. intermittent claudication, renal impairment, active proliferative retinopathy, unstable cardiac or pulmonary disease, disabling stroke, severe arthritis, etc.). * Use of or changes in medication judged by the patient or investigators to make participation in this study inadvisable. * Cardiac abnormalities identified during screening
Where this trial is running
Ottawa, Ontario and 1 other locations
- University of Ottawa — Ottawa, Ontario, Canada (Not_yet_recruiting)
- University of Ottawa — Ottawa, Ontario, Canada (Recruiting)
Study contacts
- Principal investigator: Glen P Kenny, PhD — University of Ottawa
- Study coordinator: Glen P Kenny, PhD
- Email: gkenny@uottawa.ca
- Phone: 613-562-5800
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.