No Pain, No Gain
It used to be that rhabdomyolysis was something doctors learned about in med school, and then never really dealt with it again. But more and more doctors are hearing about patients coming in with rhabdo symptoms.
Rhabdomyolysis is when an extreme effort (or impact) literally kills muscle cells. When the cells die, they leach myoglobin into your blood stream. This can lead to kidney failure. "You really have to push it really hard," says Dr. Rob Kominiarek, founder of the Alpha Male Institute, an Ohio-based men's health medical practice. "Exercise shouldn't be painful beyond feeling your muscles burn."
Dr. James Beckerman, a cardiologist in Portland, Oregon says that symptoms of rhabdomyolysis also include brown or dark red urine and feeling extremely ill. In particularly bad cases you may need dialysis treatments to recover, and the kidney damage can be permanent. The CrossFit community gets a bad rap for rhabdo, but any workout with extreme volume beyond what you're used too, like a too-hard spin class or marathon training session, could send you to the hospital.