Wrestling star Daniel Bryan announced his retirement Monday, citing multiple concussions he sustained over his 16-year career.
Speaking at a WWE event, he revealed that doctors had already found evidence that repeated head injuries had affected his brain.
"Within the first five months of my wrestling career, I already had three concussions," he said. "It gets to the point that when you've been wrestling for 16 years, that adds up to a lot of concussions."
Bryan spoke on ESPN about why he retired despite his popularity with fans.
"You have a responsibility to yourself, your family, your friends just to protect yourself," he said this week.
Bryan clarified that he did not blame the WWE for his injuries or his early retirement. He noted that the WWE even stopped him from wrestling after his last concussion despite multiple doctors saying he could compete.
Concussions from professional sports have gained attention in recent years due to new findings about Chronic Traumatic Encephalopahty (CTE).
The degenerative disease involves a buildup of the abnormal protein called tao, which is also found in Alzheimer's patients and is associated with a breakdown of brain tissue. It's believed to be caused by repetitive trauma to the brain, according to the CTE Center at Boston University. Symptoms include memory loss, confusion, impulse control problems, aggression, depression, anxiety and progressive dementia.
Multiple NFL, soccer and baseball players have been diagnosed with CTE after their death.
Bryan did not specifically mention CTE in his retirement speech because the disease can only be definitively diagnosed postmortem.