Study Finds Children Sweat at Same Rate as Adults in Extreme Heat

New research conducted by the University of Sydney has challenged long-held beliefs regarding children's susceptibility to heat-related illnesses. The study reveals that children aged 10 to 16 years are equally at risk of dehydration and hyperthermia as adults when exposed to extreme temperatures. This large-scale investigation, the most comprehensive of its kind, assessed the effects of temperatures up to 40°C on 68 children and 24 adults performing treadmill exercises under controlled conditions.

Prevailing assumptions suggested that children's higher body surface area-to-mass ratio made them more vulnerable during high heat and physical activity. However, the findings indicate that children and adults sweat similarly during such conditions, with their core temperatures rising alike. Consequently, children are not necessarily at a greater risk of dehydration or heat stroke during extreme heat events.

The study's methodology involved participants completing three different 45-minute treadmill sessions at varying intensities and environmental conditions—either 30°C with 40% humidity or 40°C at 30% humidity. Researchers monitored core temperature and dehydration levels by weighing participants before and after each trial. Dr. James Smallcombe, the lead researcher, emphasized that despite the physiological similarities, children and their caregivers should remain vigilant. Ensuring adequate hydration is essential, particularly during exercise, as children may not recognize signs of dehydration.

To assist with hydration management, the research team developed a Sweat Rate Calculator, primarily aimed at adults but also capable of estimating fluids needed for children based on factors such as height, weight, activity type, and temperature. Currently designed for cycling and running, future updates aim to include additional recreational activities.

This research underscores the importance of hydration and heat safety for children, especially amid increasing global temperatures. It shifts the focus from presumed vulnerability to informed strategies for managing heat exposure effectively. The study was published in the British Journal of Sports Medicine, reflecting its significance in understanding thermoregulation in youth during heat stress.

Source: https://medicalxpress.com/news/2025-07-children-adults-extreme.html