Key Takeaways<\/p>\n
Repetitive head injuries can cause brain cell loss and brain damage among young athletes<\/p>\n
Contact sports players had neuron loss even if they didn\u2019t develop chronic traumatic encephalopathy<\/p>\n
Researchers also observed immune cell and blood vessel changes in the brain<\/p>\n
TUESDAY, Sept. 23, 2025 (HealthDay News) \u2014 It\u2019s back-to-school time, and young athletes are preparing to hit the field once more for their school or college.<\/p>\n
However, participation in contact sports could be costing these athletes valuable brain power, according to a new study.<\/p>\n
Repetitive head impact-related brain injuries can cause a cascade of brain cell loss as well as\u00a0 inflammation and vascular damage among young athletes participating in sports like football, soccer or ice hockey, researchers reported Sept. 17 in the journal Nature<\/a>.<\/p>\n This damage can affect even players who don\u2019t develop chronic traumatic encephalopathy, the degenerative brain disease caused by repeated head impacts, researchers said.<\/p>\n \u201cThese results have the potential to significantly change how we view contact sports,\u201d said senior researcher Jonathan Cherry<\/a>, director of the digital pathology core at the Boston University CTE Center.<\/p>\n \u201cThey suggest that exposure to repetitive head impacts can kill brain cells and cause long-term brain damage, independent of CTE,\u201d he said in a news release.<\/p>\n It\u2019s been suspected that repetitive head impacts<\/a> start changing the brain years before CTE appears, but proof has been elusive because CTE can only be definitively diagnosed after death.<\/p>\n For this study, researchers analyzed frozen human brain tissue from 28 men between 25 and 51 years of age.<\/p>\n Eight of the samples came from football or soccer players who hadn\u2019t been diagnosed with CTE, and 11 from contact-sports athletes with low-stage CTE. The remaining eight samples came from men who didn\u2019t play contact sports.<\/p>\n Researchers found a striking 56% loss of neurons in young athletes participating in contact sports. The neuron loss was precisely in the brain regions that receive the hardest hits during head impacts.<\/p>\n Further, the neuron loss was observed in all athletes, regardless of whether they had CTE, researchers said.<\/p>\n The team also observed that the brain\u2019s immune cells, called microglia, became increasingly activated as athletes played contact sports for more years, and important changes in the brain\u2019s blood vessels also occurred. This could set the stage for inflammation and brain damage long before\u00a0CTE is visible.<\/p>\n \u201cYou don’t expect to see neuron loss or inflammation in the brains of young athletes because they are generally free of disease,\u201d Cherry said. \u201cThese findings suggest that repetitive head impacts cause brain injury much earlier than we previously thought.\u201d<\/p>\n And the risk posed by contact sports is noteworthy.<\/p>\n \u201cThe risk for CTE is directly related to repetitive head impact exposure in contact sports,\u201d Cherry said. \u201cThese results highlight that even athletes without CTE can have substantial brain injury. Understanding how these changes occur, and how to detect them during life, will help the development of better prevention strategies and treatments to protect young athletes.\u201d<\/p>\n The study was funded by the National Institutes of Health.<\/p>\n “What’s striking is the dramatic cellular changes, including significant, location-specific neuron loss in young athletes who had no detectable CTE,” Dr. Richard Hodes<\/a>, director of NIH’s National Institute on Aging, said in a news release.<\/p>\n “Understanding these early events may help us protect young athletes today as well as reduce risks for dementia in the future,\u201d added Hodes, who was not involved in the study.<\/p>\n More information<\/p>\n