A severe heatwave is affecting the UK this week, with the Met Office issuing only the second-ever red warning for extreme heat in parts of England and Wales. As temperatures approach 40°C, understanding the difference between heat exhaustion and heatstroke is critical. On Wednesday, the London Ambulance Service reported its highest-ever number of life-threatening emergencies, driven by the extreme heat.
Who Is Most at Risk?
Everyone can suffer from heat illness, but certain groups are more vulnerable. These include older people, babies, young children, and individuals with long-term health conditions such as diabetes or heart problems. Recognising the signs early can save lives.
What Is Heatstroke?
Heatstroke occurs when the body's temperature control system is overwhelmed by heat, leading to reduced blood flow and damage to vital organs. The NHS urges anyone with symptoms of heatstroke to seek urgent medical care immediately. Symptoms include a high body temperature or fever—usually more than 40°C—fainting or loss of consciousness, a seizure or fit, severe difficulty breathing (e.g., struggling to speak without pausing, gasping, or choking), confusion, lack of coordination, and skin that is cold to the touch even with a high body temperature.
What Is Heat Exhaustion?
Heat exhaustion happens when the body overheats and loses excessive amounts of water and salt, typically through sweating. Signs include tiredness, weakness, feeling faint, headache, muscle cramps, feeling or being sick, heavy sweating, feeling very thirsty, and heat rash. Symptoms are similar in children and adults, though children may also behave strangely. NHS Inform advises that if someone shows signs of heat exhaustion, they should be moved to a cool place, given water to sip, and cooled down with a wet cloth or fan. If symptoms worsen or do not improve within 30 minutes, medical help should be sought.
Key Differences and Actions
The main difference between the two conditions is severity: heatstroke is life-threatening, while heat exhaustion is generally less serious. However, heat exhaustion can progress to heatstroke if not treated promptly. The London Ambulance Service's record emergency calls underscore the importance of vigilance. For heatstroke, call 999 immediately. For heat exhaustion, follow first aid steps and monitor closely. Stay hydrated, avoid strenuous activity during peak heat, and check on vulnerable individuals.
