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Neuroscience For Kids

Boxing Knocks Out Brain Cells
September 15, 2006

glove A boxer who steps into the ring is at risk for brain injury. In fact, approximately 20% of professional boxers suffer chronic traumatic brain injury. These brain injuries are caused by repeated hits to the head. The severity of the symptoms (e.g., reduced mental ability, speech problems, lack of coordination) depends on the number of blows to the head, how long a boxer has fought, the skill of the boxer and the ability to take a punch. What about amateur boxers? Does the protective headgear and shorter duration of amateur fights reduce the risk of brain injury? A study of Swedish amateur boxers suggests that these young athletes DO suffer injury to neurons and glial cells of the brain.

ring A research team led by Henrik Zetterberg, M.D., Ph.D., from Goteborg, Sweden, collected cerebrospinal fluid (CSF) from 14 amateur boxers (11 men, 3 women) seven to ten days after a fight and then again after three months of rest following the fight. The CSF from the boxers was compared to the CSF collected from 10 healthy men who were not boxers. The researchers examined the CSF from all subjects for chemicals that would indicate injury to neurons and glial cells.

fight Soon after a fight, the boxers had increased CSF levels of two neuron and glial chemical markers for injury compared to CSF levels after three months of rest. Fighters who received more than 15 hits to their head or experienced grogginess during or after the fight also had higher CSF levels of these chemicals. Evidence of brain damage was found even after three months of rest: levels of the chemical marker that indicates damage to axons was higher in boxers three months after a match than levels in nonboxer control subjects.

zap These data suggest that even amateur boxing damages the brain. Although some damage can be repaired over time, evidence of damage is still seen three months after a fight. It is likely that professional boxers or those who are knocked out during a fight sustain even more damage. Further studies are needed to determine the effects of multiple fights on the chemical markers of brain damage and how these markers are associated with changes in mental ability.

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