Ambient Temperature and Thermoregulation During Exercise in Children and Youth

Summary

Little is known about how children and youth regulate body temperature during exercise across different environmental temperatures compared with young adults, including whether differences in whole-body heat exchange contribute to their responses. The goal of this clinical trial is to determine how ambient temperature affects thermoregulation during exercise in boys and girls aged 9-16 years compared with young adult men and women aged 20-25 years. Participants will complete four study visits at ambient temperatures of 22°C (Celsius; 72°F, Fahrenheit), 26°C (79°F), 31°C (88°F), and 36°C (97°F), while exercising at the same moderate-intensity metabolic heat production of 160 W/m² (W = watts, m = meters). During each visit, participants will complete four 15-minute periods of exercise (exercise bouts 1, 2, 3 and 4 respectively) separated by 15-minute rest periods. Testing will be performed in a whole-body air calorimeter, a specialized chamber that precisely measures heat lost through evaporation and dry heat exchange and the amount of heat stored in the body. These measurements, together with core temperature and heart rate, will allow researchers to determine how increasing ambient temperature affects the body's ability to lose heat and whether these responses differ between children and youth and young adults.

Conditions

• Body Temperature Changes
• Heat Stress
• Child Development
• Heat
• Physiological Stress

Interventions

OTHER

Exercise at 22°C

Participants complete intermittent exercise at a metabolic heat production of 160 W/m² in an ambient temperature of 22°C (72°F).

OTHER

Exercise at 26°C

Participants complete intermittent exercise at a metabolic heat production of 160 W/m² in an ambient temperature of 26°C (79°F).

OTHER

Exercise at 31°C

Participants complete intermittent exercise at a metabolic heat production of 160 W/m² in an ambient temperature of 31°C (88°F).

OTHER

Exercise at 36°C

Participants complete intermittent exercise at a metabolic heat production of 160 W/m² in an ambient temperature of 36°C (97°F).

Sponsors & Collaborators

• University of Ottawa

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

9 Years

Max Age

25 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2026-07-19

Primary Completion

2027-04-30

Completion

2027-06-30

Countries

• Canada

Study Locations