What should you know about effects of heat stroke?

Heat stroke occurs when the body can no longer control its temperature. The resulting heat stress can injure the brain, causing confusion, unusual behaviour, drowsiness, loss of coordination or seizures. Nausea and vomiting can worsen fluid loss. Skin may be hot and flushed, but sweating can be present or absent, so a dry skin test should not delay help. Heat stroke can follow heat exhaustion or develop suddenly during intense heat or exertion.

Call emergency services immediately. Move the person to shade or an air-conditioned place, remove extra clothing and cool them rapidly with cool wet cloths, spraying and fanning, or a cool bath if safe. Stay with them and keep cooling while help is coming. Do not give drinks to a confused, vomiting or unconscious person, and do not make them walk.

Any confusion, collapse, seizure, severe weakness, difficulty waking, repeated vomiting or suspected overheating after exertion warrants emergency care. Fever-like heat illness may need hospital monitoring even when the person seems better after cooling, because effects on the brain and organs can continue.

After recovery, ask whether the episode was heat stroke or heat exhaustion, whether you need blood tests or observation, and how medicines, hydration, clothing and work conditions affect future risk. Ask when normal exercise can resume.