Roethlisberger, who turned 36 in March and worked with a personal trainer this summer, said the goal is to prolong his career and stay fresh.
"Knees, ankles, being lighter -- those are all positives when it comes to this age and playing football, where you're pounding on your knees and you've had a couple of knee surgeries," said Roethlisberger, who suffered a torn MCL and a bone bruise in 2015 and a torn meniscus in 2016, before playing a full season last year. "Anything you can do to lighten the load on your knees is important."
Roethlisberger looks noticeably slimmer this camp and ran at a steady pace during the team's conditioning test, which requires players to record eight 100-yard runs in 18 seconds or less.
Roethlisberger confirmed he has lost weight but wouldn't reveal the number. Told that his Steelers bio still lists him at 241 pounds, his weight coming out of the 2004 draft, Roethlisberger quipped that director of communications Burt Lauten and his group "do a great job with the media guides."
Roethlisberger is chasing a third Super Bowl, and if he follows his outlook to play three to five more seasons, he'll need to extend a contract that expires in 2020. Maximizing his potential in his late 30s follows the blueprint of Tom Brady (41) and Drew Brees (40), who are still playing at high levels.
"Do everything you can to really say, 'OK, I'm going to be the best I can be physically, mentally for this season,'" Roethlisberger said. "But if you can continue looking after your body and keeping yourself healthy, it can lead to more years."