In sports, who's really 'old'?

Story highlights

  • Fans, researchers notice a trend of "older" athletes in sports, including Tom Brady's recent Super Bowl win
  • Advances in exercise science are changing athletes' training regimens to help them play into their later years
  • The earlier you start a proper exercise program, the more you can slow many effects of aging

(CNN)Tom Brady's Super Bowl victory continues a string of big wins for aging professional athletes -- and at 39 years old, Brady has said he has no plans to retire.