Does heat exhaustion cause dark urine?

Heat exhaustion can follow prolonged heat exposure, especially when sweating has caused the body to lose fluid. With less water available, urine may become darker and stronger-smelling. This can occur alongside thirst, headache, tiredness, weakness, nausea, heavy sweating, or dizziness. Dark urine is a useful clue about hydration, but it does not identify one cause by itself.

Food, supplements, medicines, urinary bleeding, liver problems, and muscle injury can also change urine colour. Brown or tea-coloured urine, pain when passing urine, or a change that persists after cooling and drinking needs medical review.

Stop activity, rest in a cool place, loosen excess clothing, and take small, frequent sips of a suitable drink if you are alert and not vomiting. Avoid alcohol and further exertion while recovering. Monitor whether the colour lightens as you recover. People with heart, kidney, or liver conditions should ask a clinician how much fluid is appropriate rather than making a large change alone.

Get urgent help for confusion, fainting, a seizure, severe weakness, inability to drink, repeated vomiting, or very hot skin. Seek prompt assessment for tea-coloured urine, very little urine, severe muscle pain, yellow skin, or blood in the urine. These findings can signal a serious heat-related or urinary problem.

Ask whether the colour fits fluid loss, how to replace fluids safely, whether medicines or supplements could be contributing, and whether urine or blood tests are needed. Mention the timing, colour description, sweating, pain, and any change in how often you pass urine.