Do I have heat stroke or heat exhaustion?

It’s easy to do: a few drinks in the sun, or a beach trip that’s gone on a little longer than planned. Still, you can get ill or even risk your life if you overheat. 

Heatstroke and heat exhaustion break the body’s natural “thermostat” and mean you get dangerously hotter and hotter.  

But what’s the difference between them? And when is it an emergency? 

Skip to: What is heat exhaustion? | What is heatstroke? | Preventing heat exhaustion | Preventing heatstroke | Heat exhaustion: what to do | Heatstroke: what to do | The final say

Heat exhaustion happens when the body gets too hot and dehydrated. ¹ 

You can no longer sweat to cool yourself down and your body temperature can rise until it’s dangerously high. 

Symptoms of heat exhaustion include: ¹ 

• A high temperature 

• Tiredness and weakness 

• Dizziness 

• Feeling or being sick 

• Becoming very thirsty 

• Fast breathing or heartbeat 

• Muscle cramps 

• Clammy skin, paleness (on lighter skin tones), or excessive sweating 

Heat exhaustion isn’t usually a medical emergency if you can cool the person down within 30 minutes. However, it can develop into heatstroke if it gets worse. 

Or if you or someone else are experiencing: skin that is very hot but not sweating; confusion, irritability, or delusion; a seizure or fit; or loss of consciousness.

Some of the most common causes of heat exhaustion are spending too long out in the sun or exercising intensely in hot weather. ² 

You can help prevent heat exhaustion by staying cool and hydrated, and doing the following:

• Drinking lots of cold drinks 

• Avoiding the sun between 11am and 3pm 

• Avoiding excess alcohol: this dehydrates you, and if you’re drinking a lot you may not associate your symptoms with heat exhaustion until it’s too late 

• Avoiding extreme exercise 

• Keeping your home as cool as possible by closing curtains, closing windows if it’s hotter outside than inside, and turning off electrical equipment that gets warm 

People who find it harder to regulate their body temperature (for example, very old or young people or those with chronic illnesses) can get heat exhaustion just by being in hot weather, even if it’s not for very long or they’re not active.  

You’ll need to take extra care to keep yourself or another at-risk person hydrated and out of the heat wherever possible.  

If you think someone has heat exhaustion, you’ll need to act quickly to help them stay safe: ¹ 

1. Move them to a cool place. 

2. Remove all unnecessary clothing, like jumpers or shoes and socks.  

3. Give them cool water or a sports drink.  

4. Cool their skin using cold water, by fanning them, or by placing ice packs wrapped in cloth on their body. The neck and armpits are good places to help the body cool down quickly. 

Stay with the person until they begin to feel better. If they don’t feel better after 30 minutes, they may have heatstroke and you should get urgent medical help. 

According to the Red Cross, you should still seek medical advice for a baby or child with heat exhaustion, even if they seem to recover fully. ³ 

Call 999 immediately if you suspect someone has heatstroke. 

Stay with them until help arrives and try to cool them down using the steps above. Do not try to make them drink anything if they are unconscious. ⁴ 

If they are unconscious or losing consciousness, put them in the recovery position until help arrives.

Heat exhaustion can happen to anyone, particularly if you’re vulnerable to hot weather. 

You must take steps to prevent it where you can, mainly by staying cool, drinking lots of fluids, and not doing extreme exercise when it’s hot. 

Get help immediately if you think you or someone else has symptoms of heatstroke, which can be life-threatening.  

Need advice on staying cool and protected this summer? Read our handpicked sun safety guides below: