With climate change fuelling more frequent and intense heatwaves, understanding the dangers of extreme heat has never been more critical. The human body's ability to regulate its core temperature can be overwhelmed, leading to potentially fatal conditions like heat exhaustion and heatstroke. This guide outlines the key symptoms and immediate actions required to safeguard health during periods of severe heat.
Understanding the Spectrum of Heat-Related Illness
Heat-related illnesses exist on a continuum, starting with milder heat stress and progressing to life-threatening emergencies. The two primary conditions to recognise are heat exhaustion and heatstroke. Heat exhaustion is the body's response to an excessive loss of water and salt, usually through heavy sweating. It is a serious condition that requires prompt intervention to prevent it from escalating.
If heat exhaustion is not addressed, it can rapidly develop into heatstroke. Heatstroke is a medical emergency where the body's temperature regulation fails, and core temperature rises to dangerous levels, typically above 40°C. At this point, the body's vital systems begin to shut down, posing an immediate risk of permanent disability or death.
Key Symptoms: Heat Exhaustion vs. Heatstroke
Recognising the difference between these conditions is vital for an appropriate response. Symptoms of heat exhaustion can include heavy sweating, pale and clammy skin, muscle cramps, fatigue, weakness, dizziness, headache, nausea or vomiting, and a fast but weak pulse. The person may appear confused or irritable.
The onset of heatstroke, however, presents a dramatic and dangerous shift. Crucially, a major red flag is the cessation of sweating; the skin becomes hot, red, and dry. Other symptoms include a throbbing headache, confusion, slurred speech, agitation, seizures, and loss of consciousness. The pulse becomes strong and rapid as the body goes into crisis mode.
Immediate Actions and Preventative Measures
If you suspect heat exhaustion, immediate action is required. Move the person to a cool, shaded place immediately. Have them lie down and loosen clothing. Cool their skin with a damp cloth or spray and fan them. Provide small sips of water or a rehydration drink if they are fully conscious. Monitor them closely.
For suspected heatstroke, the response is urgent. Call emergency services immediately (dial 999 in the UK). While waiting for help, take every possible step to cool the person down rapidly. Move them to a cool area, remove outer clothing, and cool their body with any means available: wet sheets, a cool shower, or ice packs placed on the neck, armpits, and groin. Do not give them fluids to drink if they are unconscious.
Prevention is always preferable. During a heatwave, stay indoors during the hottest part of the day, keep hydrated with water, avoid alcohol and caffeine, wear loose, light-coloured clothing, and never leave children or pets in parked vehicles. Check regularly on elderly neighbours, young children, and those with chronic illnesses, as they are most vulnerable.
The Broader Context of a Warming Climate
The increasing frequency of extreme heat events is a direct consequence of global climate change. Public health authorities worldwide are now prioritising heatwave preparedness and public education. Understanding these symptoms and responses is no longer just seasonal advice but a necessary part of community resilience in a warming world. As temperatures continue to break records, this knowledge could prove lifesaving for you and those around you.
