“Concussions happen all the time,” Favre said, via TMZ.com. “You get tackled and your head hits the turf, you see flashes of light or ringing in your ears but you're able to play—that's a concussion.”
Therefore, Favre estimates the number of concussions he suffered in the NFL is very high.
“So, based on that, [I’ve suffered] thousands,” he said. “Had to be, because every time my head hit the turf, there was ringing or stars going, flash bulbs … but I was still able to play.”