Print this topic

HealthInfo Waitaha Canterbury

Heat exhaustion & heat stroke

Heat exhaustion

Heat exhaustion is not usually serious and is caused by losing salt and water from your body after being exposed to heat for a long time. Signs of heat exhaustion include:

Treating heat exhaustion

You should start to feel better within half an hour with no long-term complications. If you do not feel better, go to your general practice team or after hours clinic.

Heat stroke

Heat stroke is less common but more serious than heat exhaustion and occurs when your body's temperature becomes dangerously high. Your body can no longer cool itself and starts to overheat. This can develop quickly with little warning.

People more at risk of developing heat stroke include:

Signs of heatstroke include:

Treating heat stroke


Heat stroke is a medical emergency. Phone 111 for an ambulance if you or someone you're caring for has any symptoms of heat stroke.

While waiting for an ambulance:

If they become unconscious, follow these instructions.

Preventing heat exhaustion and heat stroke

  HealthInfo recommends the following pages

Written by HealthInfo clinical advisers. Last reviewed December 2022.


Page reference: 53718

Review key: HIFAD-141030