The NFL season begins this week, but America’s favorite sport has been on our minds for other reasons recently. New research released in the journal BMJ reveals that 1 in 4 former NFL players in this sample had CTE, a neurodegenerative brain disease caused by repetitive head injuries. Past studies already showed that football players are at high risk for CTE, but this study – which assessed ex-NFL players who died from 2016 to 2021 – revealed that at least a quarter of those former players died with CTE, and the study’s lead author says the actual numbers are likely higher. What does that mean for players (and fans) of American football? Short Wave host Nate Rott and NPR sports correspondent Becky Sullivan find out.Interested in more sports science? Email us your question at shortwave@npr.org.Support public media with NPR+ and enjoy perks for over 25 podcasts like this one. This show’s perks include sponsor-free listening. Learn more at plus.npr.org.