Does heat exhaustion cause excessive sweating?

Heat exhaustion can develop after time in a hot environment, especially with physical activity or poor fluid replacement. Heavy sweating may occur with clammy skin, weakness, headache, dizziness, nausea, muscle cramps, thirst, or faintness. The body is losing fluid and salt while trying to lower its temperature.

Excessive sweating alone does not establish heat exhaustion. Other causes include exercise, fever, anxiety, medicines, or a condition that affects sweating. The surrounding heat and accompanying symptoms help guide the response.

Stop the activity and move to shade or an air-conditioned place. Loosen or remove extra clothing, cool the skin with wet cloths or a fan, and sip cool water or an oral rehydration drink if the person is awake and able to swallow. Rest and avoid returning to heat until fully recovered. Do not give fluids to someone who is confused, vomiting repeatedly, or unable to swallow safely.

Call emergency services for confusion, seizure, loss of consciousness, very hot skin, severe breathing trouble, or inability to drink; these may indicate heat stroke or another emergency. Seek medical advice if symptoms worsen, do not improve with cooling and fluids, or return after recovery. A person who faints should be assessed even if they wake quickly.

Ask what likely triggered the episode, how to replace fluids safely, whether medicines or medical conditions affect heat tolerance, and how to plan cooling breaks before returning to exercise or outdoor work.