Heat Exhaustion and Heatstroke: what to look for and what to do
Checked against current published health guidance — last reviewed 2026-09-23. See how we check.
Heat exhaustion causes symptoms such as headache, dizziness, heavy sweating, cramps and feeling sick, and usually gets better within 30 minutes of cooling down. Heatstroke is an emergency: call your local emergency number if someone is still unwell after 30 minutes of cooling, has hot skin that is not sweating, is confused, has a fit or loses consciousness.
Overview
Heat exhaustion happens when the body gets too hot and loses water and salt, often during hot weather or exercise. Other signs include pale, clammy skin, fast breathing or pulse, a high temperature and intense thirst.
Heatstroke is when the body can no longer cool itself. It can develop from heat exhaustion and can be life-threatening. Babies, young children, older people and people with long-term conditions are at higher risk.
What may help
- Move to a cool place
- Lie down and raise the feet slightly
- Drink plenty of water, or a sports or rehydration drink
- Cool the skin with cold water, a wet sponge or flannel, and a fan
- Put cold packs, wrapped in cloth, under the armpits or on the neck
- Stay with the person until they feel better, which should be within 30 minutes
When to see a pharmacist or GP
- Symptoms that have eased but you are still worried
- Someone at higher risk, such as an older relative or a young child, who has been unwell in the heat
When it could be an emergency
- Still unwell after 30 minutes of resting in a cool place and drinking fluids
- Hot skin that is not sweating, even when they feel too hot
- A temperature of 40°C or above
- Fast breathing or shortness of breath, confusion or a lack of coordination
- A fit (seizure), loss of consciousness or being unresponsive
If any of these apply, don't wait — call your local emergency number (see emergency numbers by country, or Red Flags in the app), or go straight to your nearest emergency department.
Want more detail, tailored to your own situation?
Look up "Heat Exhaustion and Heatstroke" in the appCommon questions
What is the difference between heat exhaustion and heatstroke?
Heat exhaustion is when the body overheats but can still cool itself, and it usually improves within 30 minutes of cooling down. Heatstroke is when the body can no longer cool itself, and it is a medical emergency.
How quickly should heat exhaustion improve?
Within about 30 minutes of moving somewhere cool, drinking fluids and cooling the skin. If not, call your local emergency number.
How can I prevent heat exhaustion?
Drink plenty of fluids, avoid the sun during the hottest part of the day, wear light, loose clothing, and avoid strenuous activity in the heat.
Who is most at risk in hot weather?
Babies, young children, older people, people with long-term conditions such as heart or lung disease, and people who work or exercise in the heat.
Official sources
Related topics
Dehydration in Older People
Signs to watch for and simple ways to help.
Headaches
Common causes, self-care, and red-flag symptoms.
Sudden Confusion (Delirium)
Sudden changes in thinking need urgent attention.
Fever in Children
Safe self-care and warning signs to watch for.
General information only, last checked 2026-09-23 — not medical advice and not a diagnosis. This page doesn't cover every cause or every person's situation; for anything specific to you or someone in your care, speak to a pharmacist, GP, or other qualified professional. See how we check. Be Health Wise is part of the Be Wise family of apps.