Exertional rhabdomyolysis is the breakdown of skeletal muscle fibres caused by intense or prolonged physical activity, leading to the release of intracellular contents such as myoglobin into the bloodstream. It is clinically important because it can result in acute kidney injury due to myoglobin-induced renal toxicity, requiring prompt recognition and management. A key complication is the development of life-threatening electrolyte imbalances, particularly hyperkalaemia, which can cause cardiac arrhythmias.