Heat stroke: spotting the symptoms and what to do
Written byH&B editorial team
Reviewed byHeeral Tomlinson
We’re all for fun in the sun, but heat stroke can be life-threatening. Stay prepped and learn the signs, plus what to do if someone shows symptoms
Summary
1What's heat stroke?
Also called ‘sun stroke’, heat stroke happens when the body gets dangerously hot.
2Heat stroke: what to do
Call 999 immediately if you think someone has heat stroke. Stay with them until help arrives and try to cool them down.
3Heat stroke vs heat exhaustion
Heat exhaustion isn’t always an emergency, but it can develop into heat stroke if it gets worse.
It’s easy to do: a few drinks in the sun or a beach trip that’s gone on longer than planned. Still, you can get ill or even risk your life if you overheat. Heat stroke breaks the body’s natural ‘thermostat’ and means you get dangerously hotter and hotter. But what are the symptoms of heat stroke? And when is it an emergency?
What’s heat stroke?
Also called ‘sun stroke’, heat stroke happens when the body gets dangerously hot. It’s potentially life-threatening and is an emergency. Heat stroke symptoms can include:1
- a very high temperature
- sickness
- dizziness
- hot skin that’s not sweating
- confusion
- a fast heartbeat
Call 999 if you or someone else has signs of heat stroke.
How to prevent heat stroke
Common causes of heat stroke are spending too long in the sun or exercising intensely in hot weather. You can help prevent heat stroke by staying cool, as well as:1
- 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 might not associate your symptoms with heat stroke until it’s too late
- avoiding extreme exercise when it’s hot
- 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
Who’s most at risk of heat stroke?
Anyone can get heat stroke. However, people who find it hard to regulate their body temperature (i.e. very old or young people or those with chronic illnesses) can get ill just by being in hot weather, even if it’s not for very long or they’re not active. You’ll need to take care to keep yourself or other at-risk people hydrated and out of the heat wherever possible.
Even pets can get heat stroke, so make sure your cats and dogs stay sun safe too!
What to do if I have heatstroke?
Call 999 immediately if you think you or someone else has heat stroke.
Heat stroke treatment is vital as you or the affected person needs to cool down as soon as possible. If it's someone else, stay with them until help arrives and try to cool them down by:1
- moving them to a cool place
- removing any unnecessary clothes
- cooling their skin using cold water, by fanning them or by applying ice packs wrapped in cloth to their body
- giving them a cool drink (only if they’re conscious)
Don't try to make an unconscious person drink anything.2 If they’re unconscious or losing consciousness, put them in the recovery position until help arrives.
What’s the difference between heat stroke and heat exhaustion?
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. Heat exhaustion isn’t usually a medical emergency if you can get cool or cool the person down within 30 minutes. However, it can develop into heat stroke if it gets worse.
Call 999 if you or someone else haven't recovered after 30 minutes in a cool place, being cooled and drinking fluids.
Does sunscreen protect you from heat stroke?
No. Wearing SPF is vital as it helps protect your skin in the sun but it doesn’t stop you against overheating and developing heat stroke. Other sun safety measures, like staying in cool areas, keeping hydrated and protecting your scalp will help protect you from heat stroke. The sun’s rays can still reach you even if the weather’s not very hot, so you should wear sunscreen outside regardless of the temperature.
How long does heat stroke last?
Heat stroke needs immediate medical attention and may have complications if it’s not treated quickly or properly. So, it can be hard to say how long heat stroke symptoms last. On the other hand, heat exhaustion should get better with the right care and you or the affected person should begin to feel better within 30 minutes of hydrating and sitting in a cool place.
The final say
Heat exhaustion can happen to anyone but 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, staying out of the sun when it’s strongest (around midday) and not doing extreme exercise when it’s hot.
Heading to a festival and worried about what to take? Take a look at our summer festival essentials for some inspo.
Disclaimer – This article provides informational advice and is not a substitute for medical care. Working with experts for accuracy, we take great care to ensure the information is up-to-date and relevant. However, you should always consult your GP or healthcare professional before using supplements or alternative products, particularly if you have medical conditions or are under supervision.
1. NHS. Heat exhaustion and heatstroke [Internet]. NHS [reviewed 2022 Aug 12; cited 2025 Apr 3]. Available from: https://www.nhs.uk/conditions/heat-exhaustion-heatstroke/
2. National Library of Medicine (NIH). Unconsciousness – first aid [Internet]. NIH [reviewed 2023 Feb 1; cited 2025 Apr 3]. Available from: https://medlineplus.gov/ency/article/000022.htm
