Rhabdomyolysis is a rare but life-threatening condition triggered by muscle injury, often involving extreme exercise. It occurs when overworked muscles begin to die and leak their contents into the bloodstream, straining the kidneys and causing severe pain. The leaked substance is a protein called myoglobin which stores oxygen in your muscles. If you have too much of it in your bloodstream, however, it can cause kidney damage. Rhabdo, as many experts call it, has been documented among soldiers, firefighters and others in physically demanding occupations. Even those people who are considered fit can be impacted, including college athletes who have been affected after grueling workouts. Statin medications are another cause of rhabdo. Now doctors are beginning to see more of it among weekend warriors, and spinning was the most common cause at one New York hospital. The medical literature indicates there are at least 46 documented cases of rhabdomyolysis in people after their first spin class. Experts agree that spinning is a great workout, but is an intense form of exercise and should not be initiated at full steam.

Symptoms of rhabdomyolysis include dark-colored urine, decreased urine output, general weakness and muscle stiffness and tenderness. Getting enough fluids into the body, often through an IV, is the first and most important treatment. People with milder cases may return to normal activities within a few weeks, but if significant kidney damage has occurred, dialysis may be necessary and damage may be permanent. For those undertaking new exercise regimes, professionals recommend starting with a less intense workout and building up, as well as knowing your physical limits. Listen to your body and recognize when it’s time to back off something that doesn’t feel right.