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Suitability of a 26 °C Indoor Environment for Mitigating Heat Strain in Young Adults

NCT07267598 · Status: RECRUITING · Phase: NA · Type: INTERVENTIONAL · Enrollment: 10

Last updated 2025-12-11

No results posted yet for this study

Summary

While an indoor upper temperature limit of 26 °C has been shown to protect heat-vulnerable older adults (DOI: 10.1289/EHP11651), this guideline has not been verified in young, habitually active adults. Public health recommendations during hot weather typically emphasize staying in cool environments, avoiding strenuous activity, wearing lightweight clothing, and maintaining adequate hydration. However, young adults may be less likely to follow these guidelines. They often do not reduce their physical activity during extreme heat events and may overdress for fashion, cultural, or religious reasons. These behaviors can impose an additional thermoregulatory burden and lead to greater physiological strain during heat exposure, even though young adults generally have a higher capacity for heat dissipation than older individuals. Accordingly, it is important to evaluate whether an indoor temperature limit of 26 °C is sufficient to protect young, habitually active adults.

To address this gap, the investigators aim to assess changes in body temperature and cardiovascular strain in young, habitually active adults (18-29 years) during an 8-hour exposure to the recommended indoor upper temperature limit of 26 °C and 45% relative humidity (humidex of 29, considered comfortable). Participants will complete two conditions:

A) seated rest while dressed in light clothing (T-shirt, shorts, and socks), and B) light exercise (stepping to simulate activities of daily living, 4-4.5 METs) performed once per hour (except for the lunch hour) while dressed in light clothing plus an additional insulating layer (sweatshirt and sweatpants).

This experimental design will allow investigators to determine the effects of added clothing insulation and light activity-representative of typical daily behaviors-on physiological strain in young adults, and to assess whether refinements to the recommended 26 °C indoor temperature limit are warranted for this population.

Conditions

  • Heat Stress
  • Physiological Stress
  • Cognitive Change

Interventions

OTHER

Simulated indoor temperature upper limit

Young adults exposed to an 8-hour simulated exposure.

Sponsors & Collaborators

  • University of Ottawa

    lead OTHER

Principal Investigators

  • Glen P Kenny, PhD · University of Ottawa

Study Design

Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Model
CROSSOVER

Eligibility

Min Age
18 Years
Max Age
29 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2025-11-07
Primary Completion
2026-03-30
Completion
2026-06-13

Countries

  • Canada

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07267598 on ClinicalTrials.gov