Physiological Strain in Young Adults During a Simulated Heat Wave

NCT ID: NCT06618352

Last Updated: 2025-06-17

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-09-28
• Study Completion Date: 2025-05-27

Brief Summary

The likelihood of exposure to overheated indoor environments is increasing as climate change is exacerbating the frequency and severity of hot weather and extreme heat events. Prolonged exposure to excessive heat stress can result in a deterioration in physiological function leading to a myriad of pathophysiological conditions (e.g., heat exhaustion, acute kidney injury, adverse cardiovascular events, heat stroke) that if left untreated can lead to death. While the relationship between extreme heat events and human health has been assessed in relation to outdoor exposure to high heat conditions, relatively little is known about the effects of daylong exposures to indoor overheating on the body's physiology.

In this study, investigators will examine the change in physiological responses (i.e., thermal, cardiovascular) in young (18-35 years) adults exposed to successive days and nights of high indoor temperatures typical of conditions recording in dwellings without air conditioning during the 2021 Western Heat Dome. Specifically, study participants will be housed in a large environmental chamber (outfitted with bed, work space, sitting area, kitchen and bathroom) for three successive days (three days and two nights) while exposed to indoor overheating where daytime temperatures will be maintained at 36°C (45% relative humidity; note: 36°C, temperatures experienced in homes without air-conditioning) for a 10-hour daytime exposure period (DAYTIME: defined as the time period from 9:00 to 19:00). For the nighttime exposure period (NIGHTTIME: defined as the time period from 19:00 to 9:00), participants will be exposed to nighttime temperatures fixed at 31°C (45% relative humidity; note: reductions in indoor temperatures during the nighttime in large urban centers range between 4-6°C). Participants will be permitted to move freely throughout the day in the chamber, but will be restricted from performing any physical activity except for the completion of a battery of tests (cardiovascular, cognitive and posture assessments performed prior to (as performed between 7:00 and 9:00) and the end (as performed between 17:00 and 19:00) of the daytime exposure). During the nighttime period, participants will be permitted to move freely until they decide to go to bed.

Conditions

Heat Stress; Physiological Stress

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Daylong exposure to extreme heat

Young adults exposed to daylong indoor overheating associated with an extreme heat event involving a 10-hour daytime exposure at 36°C (45% relative humidity) followed by a 14-hour nighttime exposure at 31°C (45% relative humidity) over three successive days with only a daytime exposure on the final day.

Group Type: EXPERIMENTAL

Simulated indoor overheating exposure

Intervention Type: OTHER

Young adults exposed to a multi-day extreme heat event

Interventions

Simulated indoor overheating exposure

Young adults exposed to a multi-day extreme heat event

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Non-smoking.
• English or French speaking.
• Ability to provide informed consent.

Exclusion Criteria

• Chronic health conditions.
• Endurance trained
• Regular exposure to heat (e.g., hot baths, sauna, regular exercise in the heat, recent vacation to area with high temperature).

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 35 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Ottawa

OTHER

Sponsor Role: lead

Responsible Party

Glen P. Kenny

Full Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Glen P Kenny, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Ottawa

Locations

University of Ottawa

Ottawa, Ontario, Canada

Countries

Canada

Other Identifiers

HEPRU-2024-09-C

Identifier Type: -

Identifier Source: org_study_id