What should you know about delayed heat stroke?

Delayed heat stroke is a medical emergency because overheating can continue to injure the brain and other organs after exposure ends. A person may seem better briefly, then develop confusion, unusual behaviour, collapse, seizures, or very hot skin. Do not wait for a thermometer reading if serious symptoms are present.

Heat stroke happens when the body cannot release heat effectively. The effects may continue after the person reaches shade or air conditioning, especially if cooling was delayed or fluids were lost. Fever-like heat, headache, dizziness and vomiting can occur, but the change in mental state is especially concerning. Heat exhaustion is less severe, yet it can progress to heat stroke when symptoms do not settle.

The person may not recognise how unwell they are. Children, older adults, people with chronic illness, and anyone exercising or working in heat need particular attention.

Call emergency services immediately. Move the person to a cool place, remove extra clothing, and cool the skin with wet cloths, cool water, fans, or ice packs wrapped in fabric. Stay with them and monitor breathing. Do not give drinks to a confused, drowsy, vomiting or unconscious person, and do not use fever medicines as a substitute for cooling. Emergency clinicians may provide rapid cooling, monitoring and IV fluid therapy.

Seek emergency help for confusion, fainting, seizure, severe weakness, trouble breathing, persistent vomiting, or inability to drink after heat exposure. Urgent assessment is also needed if the person remains unusually hot or symptoms return after initial improvement. Do not drive someone who is confused or collapsing; follow the emergency operator's instructions.

Ask what caused the episode, whether medicines or illness increased heat risk, how long to avoid strenuous activity, and how to recognise another emergency. Bring a list of medicines and describe the heat exposure, cooling measures, fluid intake and timing of symptoms.