Heat exhaustion and heatstroke need to be treated quickly.

Heat exhaustion

If you suspect someone has heat exhaustion, follow the advice outlined below.

• Get them to rest in a cool place – ideally a room with air conditioning or, if this is not possible, somewhere in the shade.
• Get them to drink fluids – this should be water or a rehydration drink, such as a sports drink; they should stop taking fluid on board once their symptoms have significantly decreased (usually within 2-3 hours).
• Avoid alcohol or caffeine because they can increase levels of dehydration.
• Use cool water (not cold) on their skin – if available, use a cool shower or bath to cool them down, otherwise apply a cool, wet flannel or facecloth to their skin.
• Loosen clothing and ensure the person gets plenty of ventilation.

Dial 999 to request an ambulance if the person doesn't respond to the above treatment within 30 minutes.

If the person is at increased risk of developing heatstroke or complications from dehydration, they should be taken to hospital. This group includes:

• children under two years of age
• elderly people
• people with kidney disease, heart failure or circulation problems
• people with diabetes who use insulin

Heatstroke

Always call an ambulance in cases of suspected heatstroke. While you are waiting for the ambulance to arrive, you should:

• move the person to a cool area as quickly as possible
• increase ventilation by opening windows or using a fan
• give them water to drink (if they are conscious), but do not give them medication, such as aspirin or paracetamol
• shower their skin with cool, but not cold, water (15-18°C); alternatively, cover their body with cool, damp towels or sheets 
• wait for medical supervision to arrive before fully immersing the person in water because the body’s response could cause them harm
• gently massage their skin to encourage circulation
• if they have a seizure (fit), move nearby objects out of the way to prevent injury (do not use force or put anything in their mouth)
• if they are unconscious and vomiting, move them into the recovery position by turning them on their side and ensuring their airways are clear

Hospital treatment

After a person with heatstroke has been admitted to hospital, the most important treatment aim is to lower their temperature as quickly as possible. This can be done in two ways:

• immersing their body in an ice bath
• spraying their body with a mist of cool water while warm air is fanned over the body; the combination of cool water and warm air encourages rapid heat loss through evaporation