What extreme heat does to your body and how to stay safe during a heatwave
By Katemarthason Okudo, June 29, 2026As Europe continues to battle an intense heatwave that has pushed temperatures beyond 40°C in several countries, health experts are urging people to take the dangers of extreme heat seriously.
Reports indicate that the ongoing hot weather has been linked to more than 1,300 heat-related deaths, highlighting the growing impact of climate change and prolonged periods of high temperatures.
According to the World Health Organization (WHO), extreme heat is among the leading weather-related causes of death globally.
While many people associate hot weather with outdoor activities and holidays, excessive heat can place enormous strain on the body. It affects everyone differently, but young children, older adults, pregnant women and people with underlying medical conditions are among those at the highest risk.
How your body responds to extreme heat
The human body naturally regulates its temperature by sweating. As sweat evaporates from the skin, it helps cool the body down. However, during a heatwave, especially when humidity is high, this cooling system becomes less effective.
When the body is unable to cool itself properly, internal temperature begins to rise. This can lead to dehydration, heat exhaustion and, in severe cases, heatstroke, a medical emergency that requires immediate treatment.
People exposed to extreme heat may experience heavy sweating, muscle cramps, dizziness, headaches, weakness and nausea. If body temperature continues to rise, confusion, fainting, seizures or loss of consciousness can occur.
Why heat can become life-threatening
Extreme heat does more than cause discomfort. It forces the heart to work harder to pump blood towards the skin in an attempt to release heat. This places additional stress on the cardiovascular system and can worsen existing heart and lung conditions.
The European Centre for Disease Prevention and Control (ECDC) notes that prolonged exposure to high temperatures also increases the risk of kidney problems due to dehydration and may affect mental wellbeing by causing fatigue, irritability and difficulty concentrating.
Heat-related illnesses can develop quickly, particularly if people remain outdoors for long periods without drinking enough fluids.
Simple ways to stay safe
Health experts recommend taking practical steps to reduce the risk of heat-related illness during very hot weather.
They drinking water regularly, even before feeling thirsty, to replace fluids lost through sweating. Wearing lightweight, loose-fitting clothing made from breathable fabrics also helps the body stay cooler.
Whenever possible, stay indoors during the hottest part of the day, usually between late morning and late afternoon. If going outside is unavoidable, seek shade, wear a wide-brimmed hat and use sunscreen to protect the skin from harmful ultraviolet rays.
Keeping living spaces cool by closing curtains during the day and opening windows when temperatures drop at night can also make a significant difference.
Watch out for vulnerable people
Heatwaves do not affect everyone equally. Older adults, infants and individuals living alone may struggle to recognise the signs of dehydration or overheating. These groups are among those most vulnerable to heat-related illnesses.
Checking on neighbours, relatives and friends during periods of extreme heat can help prevent serious health emergencies. Ensuring that vulnerable people have access to drinking water and cool environments remains one of the simplest yet most effective ways to protect lives.
A reminder as temperatures continue to rise
Scientists have warned that heatwaves are becoming more frequent and more intense in many parts of the world. Preparing for extreme temperatures is no longer only a concern for traditionally hot regions but for communities across the globe, according to the World Meteorological Organization (WMO).
Understanding how heat affects the body and taking preventive measures can reduce the risk of illness and save lives. As temperatures continue to climb, staying hydrated, limiting exposure to the sun and recognising early warning signs remain the best defence against the dangers of extreme heat.