Why Children Are More Vulnerable to Heatwaves Than Adults – and How to Keep Them Safe in United Kingdom

Biological factors mean a child’s core temperature rises faster than an adult’s – and that can result in a medical emergency. The biological systems that regulate heat in the human body are controlled by a region of the brain called the hypothalamus. It is the body’s master thermostat, acting to keep our internal temperature around 37C. It also detects when we need more fluids.

When the hypothalamus detects a rise in temperature, it initiates responses such as sweating, which cools the body through evaporation, or vasodilation, which directs warm blood to vessels near the surface of the skin, where heat can radiate away. But in children, particularly those under the age of five, the hypothalamus is not fully developed. They sweat less and do not realise when they are thirsty.

Also, children’s smaller physical size gives them a substantially greater body surface area-to-mass ratio than adults, meaning they absorb heat faster. These factors combine to make children more susceptible to heat-related illnesses such as dehydration, heat exhaustion, and heatstroke. To keep children safe during hot weather, parents and caregivers should ensure they drink plenty of fluids regularly, dress them in light and loose clothing, keep them in shaded or air-conditioned areas during peak heat hours, and never leave them in a parked car. Recognising early signs of overheating – such as excessive fussiness, fatigue, flushed skin, or rapid breathing – can help prevent a medical emergency.