Physiological Strain in Older Adults During a Simulated Heat Wave

Last updated: October 30, 2024
Sponsor: University of Ottawa
Overall Status: Active - Recruiting

Phase

N/A

Condition

Stress

Treatment

Simulated multi-day heatwave exposure

Clinical Study ID

NCT06633302
HEPRU-2024-08-A
  • Ages 65-85
  • All Genders
  • Accepts Healthy Volunteers

Study Summary

A recent report showed that maintaining indoor temperature at or below 26°C safeguards older, heat vulnerable adults against potentially dangerous increases in thermal and cardiovascular strain during an extreme heat event (PMID: 38329752). However, this proposed limit does not consider the potential cumulative effect of successive days of heat exposure, which could lead to a progressive deterioration in thermoregulatory and cardiovascular function and necessitate adjustments to upper indoor temperature limits. Further, thermal comfort and quality of sleep may be negatively impacted when bedroom temperatures exceed 24°C (PMID: 3090680). On this basis, some health agencies have recommended that bedroom temperatures at night should not exceed 26°C unless ceiling fans are available (PMID: 3090680). Currently, however, it is unknown whether indoor overheating impairs sleep quality and physiological strain on a subsequent day in older adults and, if so, whether maintaining indoor temperature at 26°C is sufficient to prevent these adverse health impacts.

With rising global temperatures and more extreme heat events, energy management strategies to limit the strain on the power grid during the daytime are now increasingly commonplace. Thus, understanding the benefits of maintaining indoor temperature at the recommend upper limits of 26°C during the nighttime only on surrogate physiological indicators of health is an important step in understanding how to optimize protection for heat-vulnerable older adults when power outages occur.

The investigators will assess the efficacy of proposed indoor temperature limits (i.e., 26°C) in mitigating increases in core temperature and cardiovascular strain over three consecutive days (3 days, 2 nights) in older adults (60-85 years) with (indoor temperatures maintained at the recommend 26°C at all times throughout the three days) and without (daytime temperature fixed at 34°C (temperature experienced in homes without air-conditioning during an extreme heat event) with nighttime temperature at 26°C) access to daytime cooling. By quantifying the effect of daylong indoor overheating on surrogate physiological outcomes linked with heat-related mortality and morbidity in older adults, the investigators can determine if refinements in the recommended upper temperature threshold is required, including best practices when power outages may occur during an extreme heat event.

Eligibility Criteria

Inclusion

Inclusion Criteria:

  • Non-smoking.

  • English or French speaking.

  • Ability to provide informed consent.

  • with or without a) chronic hypertension (elevated resting blood pressure; as definedby Heart and Stroke Canada and Hypertension Canada), b) type 2 diabetes as definedby Diabetes Canada, with at least 5 years having elapsed since time of diagnosis

Exclusion

Exclusion Criteria:

  • Episode(s) of severe hypoglycemia (requiring the assistance of another person)within the previous year, or inability to sense hypoglycemia (hypoglycemiaunawareness).

  • Serious complications related to your diabetes (gastroparesis, renal disease,uncontrolled hypertension, severe autonomic neuropathy).

  • Uncontrolled hypertension - BP >150 mmHg systolic or >95 mmHg diastolic in a sittingposition.

  • Restrictions in physical activity due to disease (e.g. intermittent claudication,renal impairment, active proliferative retinopathy, unstable cardiac or pulmonarydisease, disabling stroke, severe arthritis, etc.).

  • Use of or changes in medication judged by the patient or investigators to makeparticipation in this study inadvisable.

  • Cardiac abnormalities identified during screening

Study Design

Total Participants: 12
Treatment Group(s): 1
Primary Treatment: Simulated multi-day heatwave exposure
Phase:
Study Start date:
October 15, 2024
Estimated Completion Date:
December 31, 2026

Connect with a study center

  • University of Ottawa

    Ottawa, Ontario K1N1A2
    Canada

    Active - Recruiting

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