Environmental
Heat Exhaustion and Heatstroke
Cool an overheated person down and give fluids; if they do not improve within 30 minutes or show signs of heatstroke, call 999.
When to call 999. Call 999 if the person is confused, unresponsive, has a very high temperature, hot dry skin, a fit, or does not improve within 30 minutes of cooling — these suggest heatstroke, which is a life-threatening emergency.
What to do
- Move the person to a cool, shaded place.
- Help them lie down and raise their feet slightly.
- Give them plenty of water to drink; a sports or rehydration drink can also help.
- Cool their skin — use cool water on the skin, fan them, and put cold packs wrapped in cloth under the armpits and on the neck.
- Stay with them until they feel better, which for heat exhaustion is usually within 30 minutes.
- If they do not improve within 30 minutes, or show signs of heatstroke (confusion, hot skin, unresponsiveness), call 999 and keep cooling them.
Avoid
What not to do
Do not give alcohol or caffeine, do not leave the person in the heat, and do not underestimate confusion, drowsiness or a very high temperature — these mark the dangerous shift from heat exhaustion to heatstroke.
Afterwards and while you wait
After heat exhaustion, the person should rest, keep drinking fluids and stay cool for the rest of the day, avoiding further heat and exertion. Heatstroke always needs emergency hospital care. Prevent recurrence by staying hydrated, avoiding peak heat and taking breaks in the shade.
Education and reference only. This is general first-aid information aligned with UK guidance, not a substitute for a hands-on first-aid course or professional emergency care. In a life-threatening emergency, call 999 straight away.
Answers
Heat Exhaustion and Heatstroke: frequently asked questions
What is the difference between heat exhaustion and heatstroke?
Heat exhaustion causes tiredness, heavy sweating, dizziness and cramps and usually improves with cooling and fluids. Heatstroke is more severe, with a very high temperature, confusion or unresponsiveness, and is a medical emergency needing 999.
How do I cool someone down quickly?
Move them into the shade, give cool fluids, wet their skin with cool water, fan them, and place cold packs wrapped in cloth under the armpits and around the neck.
Related
Other environmental first aid
Sources
Where this is drawn from
- NHS — first aid
- St John Ambulance / British Red Cross first-aid guidance
- Resuscitation Council UK (where relevant)
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