Risk of Rhabdomyolysis and Kidney Injury after Intensive Exercise. Potential of Novel Biomarkers of Kidney Injury: A Narrative Review.

High-intensity interval training (HIIT), CrossFit®, strength training, and others, develop athletes' strength, speed, and endurance within a very short period of time, enabling competition at the highest sporting level. At present, they constitute one of the most widely practiced training modalities, used both in competitive and recreational sports. However, excessive intensity of such training sessions provokes substantial muscle damage (rhabdomyolysis) and may lead to renal injury, which in severe cases is diagnosed as acute kidney injury (AKI). This necessitates hospitalization and renal replacement therapy, thereby affecting athletes' health status and limiting their ability to participate in sports activities. The present work is a review of current knowledge on the phenomenon of rhabdomyolysis, its etiological factors, pathomechanisms, and health consequences, accompanied by a concise overview of emerging biomarkers of renal injury. The assessment of these biomarkers following physical exercise may provide new insights into the dynamics of post-exercise changes, indicate the severity and localization of exercise-induced renal damage, and contribute to a deeper understanding of structural kidney injury associated with strenuous physical activity-knowledge that may be applied in the prevention of exertional kidney injuries.