What happens if heat exhaustion is not treated?

Sweating removes water and salts from the body. Continued heat exposure can reduce circulating fluid and make it harder for the body to cool itself. Dizziness, nausea, weakness, headache, thirst and dark urine can signal that the body needs cooling and rehydration. Without prompt action, dehydration may become more pronounced and body temperature may rise further.

Heat stroke is an emergency. Confusion, unusual behaviour, collapse, a seizure or hot skin with severe illness requires urgent help rather than waiting for drinks to work.

Move to a cool or shaded place, loosen extra clothing and rest. Cool the skin with a fan, cool wet cloths or a lukewarm-to-cool shower. If the person is alert and able to swallow, give small, frequent sips of water or an oral rehydration drink. Avoid alcohol and strenuous activity while recovering. Medical staff may use IV fluid therapy when drinking is not enough or vomiting prevents rehydration.

Call emergency services for confusion, fainting, seizure, inability to drink, repeated vomiting, worsening weakness or suspected heat stroke. Seek prompt care if symptoms do not improve after moving to a cool place and taking fluids, or if urine remains very dark. Do not give anything by mouth to someone who is drowsy, confused or unable to swallow safely.

Ask how much recovery time to allow, when to restart exercise or outdoor work, whether an oral rehydration solution is suitable, and which medicines or health conditions increase your risk in hot weather. Ask how to recognise dehydration and heat stroke early.