Prone to heat exhaustion: prevention and warning signs

Heat exhaustion can follow work or exercise in hot, humid conditions, especially when someone has not adapted to the heat. Heavy sweating removes fluid and salts; dehydration, fever, alcohol, some medicines, illness and limited access to shade or water can add strain.

Possible symptoms include excessive sweating, headache, dizziness, weakness, nausea, thirst and cool, clammy skin. Dark urine can suggest fluid shortage, but urine colour alone cannot diagnose the cause.

Stop activity and move to a cool, shaded or air-conditioned place. Loosen clothing, cool the skin with wet cloths or fanning, and sip water or an oral rehydration drink if the person is awake and able to swallow. Rest until symptoms settle, and avoid returning to strenuous heat exposure immediately.

Prevent recurrence by taking regular breaks, drinking before thirst becomes strong, wearing light clothing, and increasing heat exposure gradually. People with medical conditions or who take regular medicines should ask a clinician how heat affects their plan.

Get urgent medical help if confusion, collapse, seizure, loss of consciousness, very hot skin, severe breathlessness or inability to drink occurs; these may indicate heatstroke or another emergency. Seek advice if symptoms do not improve promptly after cooling and fluids, or if repeated episodes occur.

Could my medicines or health condition increase heat risk? How much fluid is appropriate for me? What warning signs should my family watch for, and when should I avoid outdoor work or exercise?