How common is dark urine in heat exhaustion?

Working, exercising, or travelling in hot conditions can lead to fluid and salt loss through sweat. As the body tries to hold on to water, urine may become darker and less frequent. Heat exhaustion can also bring heavy sweating, thirst, headache, nausea, muscle cramps, weakness, dizziness, or a fast pulse. Dark urine can have other explanations, including medicines, foods, supplements, and urinary or liver conditions.

Stop activity, move to a cool shaded or air-conditioned place, loosen extra clothing, and cool the skin with a fan or cool cloths. If you are awake and able to swallow, take small frequent drinks of water or an oral rehydration drink. Do not return to heat or strenuous activity until you feel recovered. Ask for medical advice if symptoms do not settle or you have health conditions that affect fluid balance.

Call for urgent medical help if someone collapses, becomes confused, has a seizure, cannot drink, has very hot skin, or gets worse despite cooling measures. These can indicate a more serious heat-related illness. Seek prompt assessment for persistent dark urine, severe muscle pain, repeated vomiting, marked weakness, or very little urine.

Ask how your medicines or health conditions may affect heat tolerance, what fluid plan suits you, and which warning signs should prompt emergency care. If dark urine follows heat exposure repeatedly, ask whether another cause should be checked.