He admits that he vastly overtrained for his title defense at UFC 155 on Dec. 29 against Cain Velasquez. He peaked, he said, 15 days before the bout.
He took a severe beating in losing his heavyweight championship to Velasquez via a five-round decision. The morning after the bout, his urine was a very dark brown, the color of Guinness Stout beer.
He wasn't urinating blood, as some fighters do after a grueling match. Rather, the brown coloration of his urine was due to rhabdomyolysis. His muscle fiber was breaking down and getting into the blood steam.
It is a treatable condition, but it can be fatal under certain circumstances. There are numerous causes, but one is extreme physical exercise. Dos Santos trained so fiercely that he was pushing his body well beyond its natural limits.
He's consulted with experts at Nike, and brought in Alexandre Dortas, a Brazilian physiologist, to monitor various levels in his blood. After the loss to Velasquez, doctors found that his creatine kinase (known as CK) level was far too high.
Creatine kinase is an enzyme in the blood that can be used to diagnose rhabdomyolysis. The average adult male has a CK level under 300, Dortas said. He said an elite athlete can get that level as high as 350. But after the Velasquez fight, dos Santos said his CK level was over 1,400.
