Common signs of heat exhaustion

Common signs of heat exhaustion include heavy sweating, thirst, headache, dizziness, weakness, nausea, cool clammy skin and reduced concentration. Muscle cramps, dark urine and feeling faint can also occur. Heat exhaustion can develop after working, exercising or staying in a hot environment, especially when fluid and salt losses are not replaced.

Heat exhaustion happens when the body loses more fluid and heat than it can manage. Excessive sweating is an early clue, while dizziness, headache, excessive thirst and fatigue suggest that cooling and hydration are needed. Dark urine can be a sign of dehydration, although urine colour has other influences. Heat intolerance may make symptoms recur in hot conditions. Without improvement, heat illness can progress and affect alertness, so the person should not be left alone to carry on working or exercising.

Move to shade or an air-conditioned place, stop physical activity and loosen extra clothing. Sit or lie down, cool the skin with wet cloths or a fan, and take frequent small sips of cool water or an oral rehydration drink if fully alert and able to swallow. Avoid alcohol. Do not return to strenuous activity until symptoms have settled and recovery has been assessed if symptoms were significant.

Call emergency services for confusion, collapse, seizure, loss of consciousness, inability to drink, worsening symptoms or a very hot body. These features may indicate heat stroke, which needs emergency treatment. Seek medical care if symptoms do not improve promptly after cooling and fluids, or if vomiting prevents drinking. Keep monitoring breathing and responsiveness while help is arranged, and never leave an affected person alone in a hot place.

How can I return safely to work or exercise? Could a medicine or health condition increase my heat risk? Which drinks are suitable during recovery? What warning signs should prompt emergency help next time?