Heat exhaustion: symptoms, how long it lasts and what to do

The NHS lists the symptoms of heat exhaustion as follows. It says they are often the same in adults and children, and that if someone shows signs of heat exhaustion they need to be cooled down and given fluids.

• Tiredness.

• Dizziness.

• Headache.

• Feeling sick (nausea) or being sick (vomiting).

• Excessive sweating and skin becoming pale and clammy (a change in skin colour can be harder to see on brown or black skin).

• Cramps in the arms, legs and stomach.

• A high temperature.

• Being very thirsty.

• Feeling irritable.

The NHS says that if someone has heat exhaustion, follow these 4 steps and stay with them until they are better.

The NHS says a person with heat exhaustion should start to cool down and feel better within 30 minutes, and that heat exhaustion does not usually need emergency medical help if you can cool down within 30 minutes.

If they are still unwell after 30 minutes of resting in a cool place, being cooled and drinking fluids, the NHS says to call 999 because this can be a sign of heatstroke. The British Red Cross advises seeking medical advice even if the person appears to recover fully.

The NHS says heat exhaustion can turn into heatstroke, which needs to be treated as an emergency. Heatstroke is a medical emergency, and you should get immediate medical help if someone has symptoms of heatstroke.

The NHS says to get help from NHS 111 now if you or someone else have symptoms of heat exhaustion that you are struggling to treat, or you need advice.

Call 999 now if you or someone else have signs of heatstroke, including being still unwell after 30 minutes of resting in a cool place, being cooled and drinking fluids, a very high temperature, hot skin that is not sweating and might look red, a fast heartbeat, fast breathing or shortness of breath, confusion and lack of coordination, a seizure or fit, or loss of consciousness. Do not drive yourself to A&E.

While waiting for help the NHS says to wrap the person in a cool, wet sheet, or fan or sponge them with cold water. If they lose consciousness, put them in the recovery position and tell the ambulance service, check their breathing and pulse, and carry out CPR if they show no sign of life.

The NHS says the symptoms of heat exhaustion are often the same in adults and children. The British Red Cross says a child or baby with heat exhaustion might have been in the sun or heat for a long time, and might be sweating, have ashen, cool skin, a headache or dizziness, and feel sick.

The NHS heatwave advice lists babies and young children aged 5 years and under among the people most at risk. It advises checking on children, older people and people with long-term health conditions during hot weather, as they are more at risk of heat exhaustion and heatstroke.

A heatwave can affect anyone, but the NHS says some people are more vulnerable.

• Older people, especially those aged 65 and over.

• Babies and young children aged 5 years and under.

• People who are pregnant or have serious long-term conditions such as heart or breathing problems, dementia, diabetes, kidney disease, Parkinson's disease, mobility problems, mental health problems, or drug or alcohol addiction.

• People who live alone and may be unable to care for themselves.

• People on multiple medicines, or medicines that may make them more likely to be badly affected by hot weather.

• People who are already ill and dehydrated, for example from diarrhoea and vomiting.

• People who are homeless, or who work or spend a lot of time outside, particularly if physically active, or whose jobs involve manual labour.

The NHS says there is a high risk of heat exhaustion or heatstroke during hot weather or exercise. It suggests the following to prevent heat exhaustion and heatstroke, which will also prevent dehydration.

• Drink more cold drinks, especially if you are active or exercising.

• Wear light-coloured, loose clothing.

• Avoid the sun between 11am and 3pm.

• Avoid drinking too much alcohol, and avoid extreme exercise.

• Indoors on a very hot day, close curtains and windows if it is hotter outside than in your home, and turn off electrical equipment and lights that get hot.

• Have cool showers, keep your living space cool and use fans if the temperature is below 35 degrees.

Most heat exhaustion is dealt with by first aid and does not need hospital care. NHS 111 can advise if you are struggling to treat it, and 999 is the route for heatstroke. Your GP or pharmacist can advise whether your medicines make you more vulnerable in hot weather.

There is rarely a role for private care in the acute episode, but people who are repeatedly affected, such as outdoor workers or athletes, can discuss medicines and routines with their GP or an occupational health service.