Then he gets serious, recalling the damage he’s absorbed since he first started playing football when he was 12.

“What have I done?’’ Youngblood said. “I have to ask that question. You just don’t know. We haven’t defined it completely yet. That’s one of the issues we’re talking about here today.’’

Youngblood spoke during a break from the first meeting of the Mackey-White Traumatic Brain Injury Committee yesterday in Palm Beach, Fla. The committee was formed by the NFL Players Association and includes professional athletes, past and current NFL players, doctors, and researchers.

The group wants to open a dialogue on brain injuries in professional football, discuss the latest research, and begin developing recommendations to keep players safer.

The committee was named in honor of two Hall of Famers - tight end John Mackey, who has been diagnosed with Alzheimer’s disease, and defensive lineman Reggie White, who earned the nickname “The Minister of Defense’’ and died at 43 after retiring from the NFL.

“It’s something very close to my heart,’’ Youngblood said. “I became much more aware of it as I was inducted into the Pro Football Hall of Fame and got to know John Mackey more than just a guy at a cocktail party, and to see how ravaging brain injury and brain trauma can be.’’

Congress recently questioned NFL players and doctors about football head injuries. NFL commissioner Roger Goodell testified in October about his league’s concussion policies.

Since then, the league has instituted stricter return-to-play guidelines for players showing concussion symptoms; required each team to enlist an independent neurologist as an adviser; entered into a partnership with Boston University brain researchers who have been critical of the league’s stance on concussions; and conducted tests on helmets.

“You can never take the collision aspect out of the game,’’ Youngblood said. “There’s just no way, and in fact, that’s something we kind of enjoy.’’

Dr. Thom Mayer, medical director of the NFL players’ union, is serving as the committee co-chair along with Cardinals wide receiver Sean Morey.

“This committee will serve as a ‘superconductor’ of information in order to drive rapid and meaningful progress in concussions,’’ Mayer said. “We have assembled a world-class group of scientists to facilitate our work, which will benefit not only NFL players, but all those involved in all contact sports.’’

Adams died of an enlarged heart, something an echocardiogram can detect. NFL teams already give extensive physicals to players. Stress testing and echocardiograms are conducted when the results of the physical, an EKG, and family history indicate the need.

NFL medical people and outside experts who sit on the league’s cardiovascular health committee previously have discussed making echocardiograms standard. They’re doing so again, pending the final pathologists’ report on Adams.

But some cardiologists warn there could be risks, such as misdiagnoses, to making echocardiograms standard in a physical exam.