Mild heat exhaustion symptoms: what to know

Heat exhaustion develops when heat and fluid loss overwhelm the body's ability to cool itself. It commonly presents with heavy sweating, thirst, headache, dizziness, weakness, nausea, clammy skin, muscle cramps or dark urine. Symptoms may follow outdoor work, exercise, a hot room or prolonged sun exposure, and dehydration can make them worse.

A person with heat exhaustion should remain alert and able to drink. Confusion, collapse, seizure, very hot skin or inability to drink suggests a more serious heat illness and needs emergency help.

Stop activity and move to shade or an air-conditioned place. Remove unnecessary clothing, lie down with the legs raised if comfortable, and cool the skin with damp cloths, a fan or cool water. Sip water or an oral rehydration drink if fully awake and not vomiting. Have someone stay nearby and avoid returning to heat or exercise until completely recovered.

Call emergency services if the person becomes confused, faints, has a seizure, cannot drink, has trouble breathing, develops chest pain or does not improve promptly with cooling and fluids. Get medical advice for ongoing vomiting, worsening headache, persistent dizziness, very little urine or symptoms in a child, older adult or person with a serious medical condition.

How can I plan fluids and breaks for work or exercise in heat? Could a medicine or health condition increase my heat risk? What symptoms mean I should stop self-care and seek urgent treatment?