NCT06842953 Influence of Indoor Humidity on Physiological Strain in Older Adults During a Simulated Heat Wave
| NCT ID | NCT06842953 |
| Status | Recruiting |
| Phase | — |
| Sponsor | University of Ottawa |
| Condition | Heat Stress |
| Study Type | INTERVENTIONAL |
| Enrollment | 10 participants |
| Start Date | 2025-03-14 |
| Primary Completion | 2026-03-31 |
Eligibility & Interventions
Eligibility Fast-Check
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What to Expect as a Participant
You will actively receive the study intervention — which may be a drug, biologic, device, or procedure.
This trial targets 10 participants in total. It began in 2025-03-14 with a primary completion date of 2026-03-31.
⚠ This information is for research awareness only. Always consult your physician before joining any clinical trial. Participation is voluntary and you may withdraw at any time.
Brief Summary
Laboratory-based studies show that exposure to high humidity can worsen the effects of heat stress in young and older adults by impeding sweat evaporation - the main mechanism by which the human body cools itself. At high levels of humidity, the efficiency of sweating decreases causing a greater rise core temperature and burden on the cardiovascular system. In this context, increasing temperatures and humidity with climate change thus pose a potential compound risk for human health. While humidity's role in heat-health outcomes could substantially alter projections of health burdens from climate change, the impact of humidity on physiological strain in vulnerable people in relation to the indoor environment has yet to be evaluated. In a recent study delineating the physiological effects of the proposed 26°C indoor upper limit (PMID: 38329752), relative humidity was set to 45% in all conditions based on indoor humidity standards by the American Society of Heating and Air-Conditioning Engineers. However, it is unknown whether a refinement of the recommended indoor temperature limit of 26°C is required in situations where humidity cannot be maintained at this level. On separate occasions, the investigators will assess the change in body temperature and cardiovascular strain in older adults (65-85 years) exposed for 10 hours at the recommended indoor temperature limit of 26°C and 45% relative humidity (equivalent humidex of 29 (considered comfortable)) (experimental condition A), to 26°C with a relative humidity of 15% (equivalent humidex of 23 (considered comfortable); humidex is used to measure the perceived temperature taking into account the humidity)) (experimental condition B), to 26°C with a relative humidity of 85% (equivalent humidex of 37 (considered somewhat uncomfortable)) (experimental condition C), and to 31°C and 45% relative humidity with an equivalent humidex of 37 (considered somewhat uncomfortable) that is similar to experimental condition C. With this experimental design, investigators will assess the effects of indoor humidity in driving human heat strain and identify whether refinements in the recommended 26°C indoor temperature limit may be required. Further, by evaluating changes in relation to ambient conditions with a similar humidex, the investigators can assess how individuals perceive and respond to both heat and humidity.
Eligibility 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
Contact & Investigator
Frequently Asked Questions
Who can join the NCT06842953 clinical trial?
This trial is open to participants of all sexes, aged 60 Years or older, up to 85 Years, studying Heat Stress. Full inclusion and exclusion criteria are listed in the Eligibility Criteria section. Always confirm your eligibility with the research team before applying.
Is NCT06842953 currently recruiting?
Yes, NCT06842953 is actively recruiting participants. Contact the research team at gkenny@uottawa.ca for enrollment information.
Where is the NCT06842953 trial being conducted?
This trial is being conducted at Ottawa, Canada.
Who is sponsoring the NCT06842953 clinical trial?
NCT06842953 is sponsored by University of Ottawa. The trial plans to enroll 10 participants.