Impact of Indoor Overheating on Physiological Strain in Children

NCT07261202 | Recruiting

• 1 other identifier: HEPRU-2025-10-A
• Study Type: interventional
• Target: 10
• Locations: 1 country
• Sites: 1

Brief Summary

Communities worldwide are experiencing increasing heat extremes that challenge the limits of human thermoregulation, particularly among vulnerable populations such as children. Compared with adults, children are more susceptible to heat related illness due to less efficient thermoregulatory systems and difficulty recognizing early signs of heat stress. In addition, prolonged heat exposure can adversely affect their mental health, contributing to cognitive decline, heightened anxiety, and irritability. As children spend substantial time in hot environments at school and at home, and as these conditions intensify with climate change, actions to safeguard their health are essential. Yet our understanding of heat exposure effects in children remains incomplete, hindering the development of evidence based strategies to protect them. To address this gap, the investigators aim to evaluate whether an indoor temperature limit of 26 °C (45 percent relative humidity), the upper threshold recommended to protect older adults, can effectively prevent dangerous increases in physiological strain and declines in cognitive function in children during a simulated daylong heatwave. The preliminary study will assess physiological and cognitive responses in children aged 10 to 15 years during a 6 hour exposure (approximating a typical school day) to two conditions: (1) the recommended indoor temperature upper limit (26 °C) and (2) a high heat condition representative of homes and schools without air conditioning during extreme heat events (36 °C). In both conditions, children will remain seated at rest while wearing light clothing (t shirt and shorts), with the exception of performing 15 minutes of stepping exercise (6-6.5 METS) each hour (excluding the lunch period) to reflect typical daily activity in a school setting. This experimental design will allow investigators to determine whether maintaining indoor temperatures at the recommended upper limit for older adults sufficiently mitigates physiological strain in children.

Conditions

Physiological Stress; Cognitive Change; Heat Stress

Keywords

Indoor overheating; Indoor temperatures; Heat wave; Thermoregulation; Adolescent; Heat strain; Heat vulnerability; Hyperthermia; Youth; Thermal comfort; Physical activity

Outcome Measures

Primary Outcomes (1)

• Core temperature (Peak) during daylong exposure to indoor overheating

  Peak visceral temperature (15 min average) during exposure. Visceral temperature is measured continuously throughout the 6 hour exposure to the simulated indoor overheating.

  End of 6 hour daylong exposure

Secondary Outcomes (28)

• Profiles of Mood States (POMS) during daylong exposure to indoor overheating

  At the start (hour 0) and end of 6 hour daylong exposure

• Environmental Symptoms Questionnaire (ESQ) during daylong exposure to indoor overheating

  At the start (hour 0) and end of 6 hour daylong exposure

• Perceived exertion scale during daylong exposure to indoor temperature limit.

  At the start (hour 0) and end of 6 hour daylong exposure

• Activity levels during daylong exposure to indoor overheating

  End of 6 hour daylong exposure

• Feel good scale during daylong exposure to indoor overheating

  At the start (hour 0) and end of 6 hour daylong exposure

Study Arms (2)

Exposure to indoor temperature upper limit of 26°C

EXPERIMENTAL

Participants exposed daylong (6 hours) to an indoor temperature maintained at 26°C and 45% relative humidity (humidex equivalent of 29).

Other: Simulated exposure to indoor overheating

Exposure to hot indoor environment of 36°C

EXPERIMENTAL

Participants exposed daylong (6 hours) to an indoor temperature maintained at 36°C and 45% relative humidity (humidex equivalent of 45).

Other: Simulated exposure to indoor overheating

Interventions

Simulated exposure to indoor overheating OTHER

Children exposed to a 6-hour simulated heat exposure

Exposure to hot indoor environment of 36°C; Exposure to indoor temperature upper limit of 26°C

Eligibility Criteria

• Age: 10 Years - 15 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)

You may qualify if:

• English or French speaking.
• Ability to provide informed assent.

You may not qualify if:

• Chronic health conditions
• Endurance exercise training (greater than 3 sessions of vigorous exercise training per week for 30 minutes or more)
• Restrictions to physical activity

Sponsors & Collaborators

• University of Ottawa: lead

Study Sites (1)

University of Ottawa

Ottawa, Ontario, K1N 6N5, Canada

RECRUITING

MeSH Terms

Conditions

Heat Stress Disorders; Hyperthermia; Motor Activity

Condition Hierarchy (Ancestors)

Wounds and Injuries; Body Temperature Changes; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Behavior

Study Officials

• Glen P Kenny, PhD

  University of Ottawa

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Glen P Kenny, PhD

CONTACT

613-562-5800; gkenny@uottawa.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Full Professor, University Research Chair

Study Record Dates

• First Submitted: November 21, 2025
• First Posted: December 3, 2025
• Study Start: November 8, 2025
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): December 31, 2026
• Last Updated: April 23, 2026

Record last verified: 2026-04

Locations

CA (1)