First aid treatment for heat exhaustion

Heat exhaustion happens when the body loses fluid and salt through sweating and cannot cool itself well. People may develop heavy sweating, weakness, dizziness, headache, thirst, nausea, muscle cramps, cool clammy skin, or dark urine. Symptoms often follow exertion or time in a hot, poorly ventilated place.

An alert person who can swallow may benefit from water or an oral rehydration drink. Do not give drinks to someone who is confused, vomiting repeatedly, having a seizure, or unable to swallow safely.

Stop activity and take the person indoors or into shade. Remove unnecessary outer clothing, fan them, and place cool wet cloths on the neck, armpits, and skin. Offer small, frequent sips rather than forcing a large drink. Stay with them and reassess their alertness and breathing.

If they improve, rest in a cool environment and avoid returning to heat or strenuous exercise that day. A clinician can assess dehydration, medicines, and other factors that increase heat risk.

Call emergency services if the person becomes confused, faints, has a seizure, cannot drink, has worsening symptoms, or feels extremely hot with altered behaviour. These signs may indicate heatstroke, which requires urgent medical treatment.

Seek medical advice if symptoms do not clearly improve after cooling and fluids, or if there is persistent vomiting, very little urine, or marked weakness. Do not leave a deteriorating person alone.

Ask how to adjust activity in hot weather, whether your medicines affect sweating or fluid balance, and which drinks are suitable if you have heart or kidney problems.