If you watched the Mayweather vs. McGregor fight or saw the technical knockout online, you probably noticed a weary, not-entirely conscious Conor McGregor stumbling around the ring as Mayweather continued to pummel him. Yet despite the global spectacle, neurologists say something grim could be going on in the brains of fighters like McGregor. According to a study presented at an American Academy of Neurology conference, blood samples from 291 current professional fighters showed indications of brain injury.
“Our study looked at data over a five-year period and found elevated levels of two brain injury markers in the blood,” lead author Charles Bernick said in a press release. “Now the question is whether they may signify permanent traumatic brain injury with long-term consequences.” The indicators in question are neurofilament light chain and tau; these biomarkers only appear in the blood of fighters and NFL players when they’ve been injured. Their presence can indicate the future development of neurodegenerative diseases, such as dementia and Huntington’s disease.
Among their findings, Bernick’s team discovered that neurofilament light chain (Nfl) levels were “40 percent higher in active boxers than non-fighters.” Sparring within two weeks of the blood sample also elevated NfL, and fighters with heightened NfL scored worse on computerized cognition tests.
Although the July study focused on active fighters, the prognosis for retirees isn’t good: A 2014 study in Alzheimer’s & Dementia tested the brains of 13 retired boxers and one MMA fighter and found serious cognitive impairments with reaction time, processing speed, and memory. The problem of neurodegenerative diseases in high-impact sports has become so evident that 30 former NFL players are donating their brains to science.
The fighters in the latter study averaged 45.2 professional fights over 14.3 years. McGregor’s only had 25 pro fights, including the bout with Mayweather, but as more research emerges about the effects of trauma on the brain, it doesn’t bode well for the future health of pro fighters.