One story after another keeps coming out that proves how life-altering brain injuries are. Athletes who spent years playing high-contact sports provide impactful evidence that not only is football dangerous, but the head injuries sustained in the sport can lead to lethal health problems.

From the outside looking in, some might think that a player hits his head, gets up again and is okay. Just because there isn’t blood after a tackle doesn’t mean there isn’t serious damage inside a player’s brain. Scientific research supports that scary fact.

There have been recent suicides among former NFL players. Most recently, former star player Junior Seau shot himself in the chest in California. After his death, scientists studied his brain and found evidence of a serious condition called chronic traumatic encephalopathy. CTE has been found in other players after their deaths as well.

Scientists say that the brain disease kills brain cells and even shrinks a victim’s brain. The players who suffered from CTE showed symptoms of irritability, dementia, depression and other significant personality changes. It isn’t just football players who are at-risk of suffering from CTE; it’s anyone who sustains multiple blows to the head.

CTE isn’t diagnosed until after death. Autopsies of deceased players likely leave many surviving athletes worried about the state of their brains. Thousands of former NFL players follow studies of brain injuries and are fighting for justice and a safer NFL. They are suing the league for not better informing them about and protecting them from the damage of head injuries.

Source: Bloomberg, “Ex-NFL Player Junior Seau Had Brain Disease From Head Injuries,” Stephanie Armour & Erik Matuszewski, Jan. 10, 2013