Dark urine after exercise: what to know

Sweating reduces the water available to make urine, so the next sample may look darker and smell stronger. Heat, long sessions and limited drinking increase this effect. Dark brown or cola-coloured urine after strenuous activity can also occur when muscle tissue releases pigment into the bloodstream. That problem may be accompanied by marked muscle soreness, weakness or swelling and can affect the kidneys. Exercise does not make every dark urine episode harmless.

Stop exercising, move to a cool place and drink at a comfortable pace if you are alert and able to swallow. Do not return to training while urine remains unusually dark or muscles are painful and weak. Note the session intensity, heat exposure, fluid intake, supplements and medicines. If the colour does not improve with rest and normal hydration, contact a clinician promptly. Testing urine and blood can check kidney function and muscle breakdown.

Seek urgent care for cola-coloured urine, very little urine, severe muscle pain, weakness, swelling, confusion, fainting, chest symptoms, or vomiting that prevents drinking. Heat-related confusion or collapse is an emergency. Even without these signs, arrange prompt advice if dark urine follows a demanding workout, returns with exercise, or lasts beyond the recovery period.

Ask whether your symptoms could reflect dehydration, heat illness or muscle pigment. Ask if you need urine and blood tests, when to resume exercise, and how to adjust fluids around training safely.