Can heat exhaustion cause heat stroke?

Heat exhaustion may cause heavy sweating, headache, dizziness, nausea, weakness and cramps. Heat stroke is more dangerous: the person may become confused, unusually drowsy, uncoordinated, faint or have a seizure. Skin can feel very hot, and sweating may be present or absent. A change in alertness is an emergency warning, whether or not the person has measured their temperature. Heat can impair judgment, so someone affected may not recognise how ill they are. Read more about [Heat Exhaustion](/conditions/heat-exhaustion/).

Stop activity and move the person to a cool place. Remove unnecessary clothing, wet the skin, fan them and place cool packs near the neck, armpits and groin. If they are awake and can swallow safely, offer small sips. Never give drinks to someone who is confused, vomiting repeatedly, fitting or unconscious. Stay with them and note when the symptoms began.

Call emergency services immediately for confusion, collapse, seizure, loss of consciousness, severe breathing difficulty or very hot skin with worsening illness. Continue active cooling while help is coming. Do not leave the person alone or delay care to see whether rest makes the symptoms disappear.

Ask how to recognise early heat illness, when you can safely return to exercise, and whether medicines or medical conditions affect your response to heat. Tell the clinician about the setting, physical activity, fluids taken, vomiting, fainting and any change in behaviour.