Exertional rhabdomyolysis

Exertional rhabdomyolysis (ER) is the breakdown of muscle from extreme physical exertion. It is one of many types of rhabdomyolysis that can occur, and because of this the exact prevalence and incidence are unclear. Exertional rhabdomyolysis (ER) is the breakdown of muscle from extreme physical exertion. It is one of many types of rhabdomyolysis that can occur, and because of this the exact prevalence and incidence are unclear. ER is more likely to occur when strenuous exercise is performed under high temperatures and humidity. Poor hydration levels before, during, and after strenuous bouts of exercise have also been reported to lead to ER. This condition and its signs and symptoms are not well known amongst the sport and fitness community and because of this it is believed that the incidence is greater but highly underreported. Risks that lead to ER include exercise in hot and humid conditions, improper hydration, inadequate recovery between bouts of exercise, intense physical training, and inadequate fitness levels for beginning high intensity workouts. Dehydration is one of the biggest factors that can give almost immediate feedback from the body by producing very dark-colored urine. Exertional rhabdomyolysis results from damage to the intercellular proteins inside the sarcolemma. Myosin and actin break down in the sarcomeres when ATP is no longer available due to injury to the sarcoplasmic reticulum. Damage to the sarcolemma and sarcoplasmic reticulum from direct trauma or high force production causes a high influx of calcium into the muscle fibers increasing calcium permeability. Calcium ions build up in the mitochondria, impairing cellular respiration. The mitochondria are unable to produce enough ATP to power the cell properly. Reduction in ATP production impairs the cells ability to extract calcium from the muscle cell. The ion imbalance causes calcium-dependent enzymes to activate which break down muscle proteins even further. A high concentration of calcium activates muscle cells, causing the muscle to contract while inhibiting its ability to relax.