Physiological Responses in Young and Older Adults During a Prolonged Simulated Heatwave

Summary

Climate change not only affects the planet's natural resources, but also severely impacts human health. An individual's ability to adequately cope with short- or long-term increases in ambient temperature is critical for maintaining health and wellbeing. Prolonged increases in temperature (heatwaves) pose a serious health risk for older adults, who have a reduced capacity to efficiently regulate body temperature. However, information regarding the impact of age on body temperature regulation during prolonged exposure to extreme heat is lacking, as is research on the effectiveness of interventions aimed at reducing heat strain in such situations. This project will address these important knowledge gaps by exposing healthy young and older adults to a prolonged (9 hour) heat exposure, with conditions representative of heatwaves in temperate continental climates. An additional cohort of older adults will complete the same heatwave simulation but will be briefly (2 hours) exposed to cooler conditions (22-23°C) mid-way through the session (akin to visiting a cooling centre or cooled location). The investigators will evaluate age-related differences in the capacity to dissipate heat via direct air calorimetry (a unique device that permits the precise measurement of the heat dissipated by the human body) and their effect on the regulation of body temperature. The investigators anticipate that older adults will exhibit progressive increases in the heat stored in the body throughout the simulated heatwave, resulting in progressive increases in body core temperature. Further, older adults exposed to brief-mid day cooling will rapidly gain heat upon re-exposure to high ambient temperatures. As a result, by the end of exposure body temperatures will be similar to the group not removed from the heat.

Conditions

• Aging
• Heat Stress
• Physiological Stress

Interventions

OTHER

Simulated heatwave exposure

Young and older adults (no cooling) are exposed to a 9-hour simulated exposure.

OTHER

Simulated heatwave exposure with mid-day cooling

Older adults (cooling) are exposed to a 9-hour simulated exposure with mid-day ambient cooling.

Sponsors & Collaborators

• University of Ottawa

  lead OTHER

Principal Investigators

• Glen P Kenny, PhD · University of Ottawa

• Ronald J Sigal, MD, MPH · University of Calgary

Study Design

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2019-01-01

Primary Completion

2021-04-02

Completion

2021-04-02

Countries

• Canada

Study Locations