Researchers report that even the relatively mild blows to the head incurred by amateur boxers appear to cause brain damage.
The researchers analyzed the cerebrospinal fluid of 14 amateur boxers for protein markers of brain injury. Levels of one particular marker for brain damage, known as neurofilament light (NFL) protein, were four times higher in boxers within 10 days of the fight than in healthy non-boxers.
In the study, the boxers were tested both after a fight and then again three months after their last match. NFL levels were still elevated three months later.
Researcher Max Hietala, M.D., Ph.D., of Sahlgrenska University Hospital in Goteborg, Sweden, tells WebMD that the Swedish boxers studied were wearing helmets that were much better padded than those generally used in U.S. amateur fights.
"Regardless of the gear, if they got hit more than 15 times, it was like having a mini-stroke," he says.
NFL levels were up to eight times higher in amateur boxers who received more than 15 high-impact hits to the head after a match than after the three-month rest.
"Given that amateur fights are much shorter and generally involve milder head blows than pro fights, you can just imagine what's happening to professional boxers," James Kelly, M.D., a visiting professor of neurosurgery at the University of Colorado in Denver, tells WebMD. Kelly was not involved with the work.
The study was presented at the American Academy of Neurology's annual meeting.
Hietala says a well-thrown punch carries more than a half-ton of force. He says that the hits cause brain cells to die. Then they leak proteins into the cerebrospinal fluid.
"If you get a concussion, you'll also have elevated NFL levels, but there's nothing you can do," Hietala says. "With boxing, you can."
"We've seen some studies [on this topic before], but this is much more scientifically detailed, with finer testing," Kelly says. "This is truly worrisome."
Not all the news is distressing: The researchers found that no evidence of increased levels of NFL or other markers of brain injury in medical students who volunteered to repeatedly hit a soccer ball with their heads.
"Our conclusion is that hitting a soccer ball with your head is not dangerous," Hietala says.
By Charlene Laino
Reviewed by Louise Chang, M.D.
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