Examples of heat exhaustion

Heat exhaustion develops when sweating and heat exposure cause the body to lose water and salts faster than they are replaced. A person may feel weak, dizzy, thirsty or headachy, with clammy skin, nausea or unusually dark urine. Heat intolerance can make hot environments harder to tolerate, but it does not explain every episode of dizziness or sweating.

Move to shade or an air-conditioned place, loosen unnecessary clothing and cool the skin with wet cloths or a fan. Sip water or an appropriate rehydration drink if the person is awake and able to swallow. Stop exercise and rest. Do not leave someone with symptoms alone, and monitor whether alertness and discomfort improve after cooling.

Call emergency services for confusion, seizure, collapse, loss of consciousness, very hot skin, or inability to drink. These can signal heatstroke, which needs immediate treatment. Arrange medical assessment if symptoms do not improve promptly with cooling and fluids, or if vomiting prevents drinking. Dark urine, marked thirst or ongoing dizziness can indicate dehydration.

Ask whether medicines or a health condition increase heat risk, how much activity is appropriate, and which warning signs should lead to emergency care.