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First aid · Australia

Heat illness

Heat illness can worsen quickly. Stop exertion, move the person to shade or a cool room and start active cooling. Call 000 for confusion, changed behaviour, collapse, seizures, reduced consciousness, inability to drink, suspected heatstroke or failure to improve quickly. Give cool fluids only if the person is fully conscious and able to swallow.

Medical emergency? Call 000

What to do

  1. Stop activity; move to a cool place

    Stop activity, move the person to shade or air conditioning and stay with them.

  2. Call 000 early for serious signs

    Send for an ambulance early for confusion, changed behaviour, collapse, seizures, reduced consciousness, suspected heatstroke or symptoms that do not improve quickly. Do not stop cooling while waiting.

    Take care. Do not wait for sweating to stop before treating serious heat illness; a person may still be sweating.

    Take care. Do not delay 000 while waiting to measure a temperature or while trying one cooling method.

  3. Start active cooling

    Remove or loosen excess clothing. Wet or spray the skin with cool water, fan continuously and use cool packs where available. For a person over 5, cold-water immersion from the neck down for up to 15 minutes is the most effective option when safe; for a child 5 or under, use a tepid bath, wet cloths and a fan.

  4. Only offer drinks if safe to swallow

    Give cool water or an electrolyte drink only when the person is fully conscious and able to swallow. Give no drinks to someone confused, drowsy, vomiting or unable to protect their airway.

    Take care. Do not give drinks to a confused, drowsy, vomiting or unconscious person.

  5. Keep checking response and breathing

    Keep assessing consciousness, airway and breathing. If the person becomes unresponsive and is not breathing normally, call 000, start CPR and follow the call-taker.

    Take care. Do not leave the person alone or use aspirin, ibuprofen or paracetamol to lower heatstroke temperature without medical advice.

Know when to act

When to get help

  • Call 000 for confusion, changed behaviour, collapse, seizures, reduced consciousness, inability to drink, suspected heatstroke, severe worsening or heat illness that does not improve quickly with cooling.

Children and babies

  • Babies and children can become seriously unwell quickly. For children 5 and under, use tepid water, wet cloths and fanning rather than cold-water immersion, and seek help early for altered behaviour, drowsiness, poor drinking or worsening symptoms.

Keep checking

  • Continuously reassess consciousness, airway, breathing and ability to swallow while cooling. Keep the person with someone until they recover or ambulance care takes over.

What you may notice

  • Heat exhaustion can cause weakness, dizziness, headache, nausea, thirst, heavy sweating and cool or clammy skin.
  • Heatstroke can cause confusion, changed behaviour, slurred speech, poor coordination, collapse, seizures or reduced consciousness.
  • Serious heat illness can occur with or without ongoing sweating; the person may be hot, weak, confused or unable to drink.

When help arrives

  • Call 000 early for suspected heatstroke and keep actively cooling while waiting.
  • Tell responders the heat exposure, activity, changes in behaviour, fluids given and cooling methods used.

Other useful answers

What is the difference between heat exhaustion and heatstroke?

Heat exhaustion may cause weakness, dizziness, nausea, headache and clammy skin. Confusion, changed behaviour, collapse, seizures or reduced consciousness suggest heatstroke and need 000 plus active cooling.

Sources and last update

Content updated: August 2026.

These sources inform the guidance. This independent resource is not a substitute for a first aid course or medical assessment. An editorial update is not independent clinical review. Source organisations have not endorsed this site.

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