Fainting from heat exhaustion

Heat exhaustion develops when the body struggles to release heat and replace fluid lost through sweating. Affected people may have excessive sweating, thirst, headache, dizziness, nausea, weakness, cool clammy skin, or dark urine. Fainting may happen after exertion or prolonged standing, but it should not be casually attributed to heat if the story is unusual.

Heat exhaustion can progress to heat stroke. Confusion, unusual behaviour, a seizure, or loss of consciousness are especially concerning because the person may no longer be able to cool themselves or drink safely.

Stop activity and move into shade or an air-conditioned area. Lay the person flat with legs raised, remove extra clothing, and cool them with wet cloths, a fan, or cool packs wrapped in fabric. Check breathing. If fully awake, give small frequent sips of water or oral rehydration fluid. Do not leave them alone, and do not give drinks to an unconscious or confused person.

Call emergency services for fainting with confusion, seizure, difficulty breathing, chest pain, severe headache, repeated vomiting, injury, or failure to wake promptly. Get urgent assessment when cooling does not clearly improve symptoms, when the person cannot keep fluids down, or when fainting recurs. Avoid returning to exercise or outdoor heat until medically advised.

Ask how to prevent another episode, whether medicines or an illness increased heat risk, and whether dehydration or an abnormal heart rhythm needs checking. Note the activity, weather, sweating, fluid intake, symptoms before collapse, and recovery pattern.