Heat exhaustion and rhabdomyolysis

Rhabdomyolysis occurs when damaged muscle releases substances into the bloodstream, often after intense exertion in heat, prolonged muscle strain or severe dehydration. Heat exhaustion commonly brings sweating, weakness, thirst, headache and dizziness, while muscle tenderness, marked weakness or urine that becomes tea-coloured raises concern for muscle injury. Kidney problems can follow, so this is not something to monitor casually at home.

Stop exercise, move somewhere cool and remove unnecessary layers. Rest and cool the body. If fully alert and not vomiting, take small, regular sips of fluid; avoid forcing a large amount at once. Do not return to training, use alcohol, or take unplanned medicines for pain before speaking with a clinician. Keep track of urine output and changes in muscle pain or strength.

Arrange urgent medical assessment for dark urine, very little urine, increasing muscle pain, swelling, profound weakness, fainting, confusion or repeated vomiting. Call emergency services for collapse, seizure, severe breathing difficulty or altered awareness. A clinician may need blood and urine tests and treatment to protect kidney function; home cooling does not replace that assessment.

Ask when you can safely resume exercise, whether medicines or supplements affect muscle or kidney risk, and what hydration and heat-acclimatisation plan is appropriate. Tell the clinician about the activity, heat exposure and timing of urine changes.