And he figures it will help the next phase of his comeback.
Bosh said Thursday that he no longer needs to take blood-thinning medication, which means he can be a full participant when training camp opens Tuesday.
"I feel a little bit of urgency," Bosh said. "I don't have much longer to play this game. That's just a fact. I wanted to make sure I had the ability to hit the ground running when the season starts. Most people say, 'Oh, how's he going to react. He had clots.' I look at it as, I had rest. I had to build back up, but I had rest, mentally and physically."
Bosh missed the final 30 games last season after a blood clot was diagnosed on his left lung, and he has been back in on-court workouts for about two months but not cleared for contact until now.
He took a blood thinner for several months as part of his recovery. Athletes in contact sports typically cannot take blood thinners because of the higher risk of bleeding, a common side effect of such drugs.
Bosh's weight was listed as 235 pounds last season. He said he is now closer to 245, which, with camp looming, he expects to be temporary because of all the running and conditioning drills.
The added muscle, however, will be a plus when it's time to start getting physical around the rim.
"I just wanted to make sure I came in with enough cushion to sustain contact," Bosh said.
Bosh spoke of how he sees the game differently now, after it was taken away for a few months. He is not genetically prone to clots, though if tests showed he was, his career could have been over.
His message now to the Heat is simple: Nothing is promised.
Heat coach Erik Spoelstra said Bosh's words are already resonating.
"He's been reinvigorated," Spoelstra said. "He's had an opportunity to train. He's obviously had an opportunity to see a different perspective ... and I already thought he had great perspective. But when you have something that you love taken away from you and all you're thinking about is your health and whether you're going to be able to have a normal life with your family, that's a whole different perspective."
A 10-time NBA All-Star, Bosh was averaging 21.1 points per game last season when the pain in his side wouldn't go away and his wife convinced him to seek medical help.
He is entering his 13th NBA season and will be expected to help the Heat try to get back into playoff-contending form after his illness and injuries to Dwyane Wade and others all played a role in Miami finishing with a 37-45 record.
"I have a very good feeling for how things are going to go," Bosh said.
Bosh spoke Thursday at an event to announce his partnership with Janssen Pharmaceuticals, the makers of the blood-thinning drug Xarelto, which he was taking. The Heat also have partnered with the company, and Bosh said he will be an advocate for awareness of clot-related issues and treatments.
"This affects so many people," Bosh said. "I don't want people to lose their life or go through what I went through."