Unfortunately for Watt, going 100 percent on every play in every game for 16 weeks takes its toll on your body, and over the offseason, Watt found out just how bad that toll can be.
After the 2015 season ended, Watt underwent surgery and things got so bad during rehab that he actually thought he was going to have to retire.
"When I was in Philadelphia after the first surgery [in January], there were some days there where I really, really questioned whether or not I would ever be able to play again," Watt said on Wednesday, via ESPN.com. "Just some of the stuff we were dealing with from a rehab standpoint. And just the way that the recovery was going early on."
Just in case you lost track or didn't hear, Watt played most of the 2015 season with a herniated disk and five fully or partially torn core muscles, including a tear in his groin muscle.
Those injuries led to an ugly surgery.
"A few of (the abdominal muscles) were fully off the bone," Watt said, via NFL.com. "A few of them were partial torn. That was pretty serious stuff."
The defensive end was in so much pain after surgery that he couldn't even get out of bed.
"There was a very low point there. It was tough. I was in a hotel room in Philadelphia for I think 10 days straight not being able to really walk or do anything," Watt said. "There was definitely a tough point there."
It wasn't until February, almost three weeks after his surgery, that Watt knew for sure that he'd be able to return to football.
"One morning I woke up and all of a sudden, one thing I hadn't been able to do since the surgery was lift my right leg straight up in the air. ... And that morning I did it," Watt said. "I called [Texans rehab coordinator Rolando Ramirez] right away and sent him a video and I was like, 'Look.' And so then I got up and tried some other stuff, and I actually did up-downs in the room, right there and I sent him a video of it. And I was like, dude, it worked."
Of course, that wasn't the end of the offseason pain for Watt. The defensive end also underwent back surgery in July.
Although there were reports that Watt might miss the Texans' regular season opener, the man who's never missed a game in his NFL career scoffs at that.
"There was never a doubt [that I would play]," Watt said. "Those guys were awesome in helping me and also awesome in being willing to have an aggressive approach. After a surgery, the rehab can go one of many ways, and these guys were willing to accept my aggressive style, and we did it in a smart fashion, but we did it in a way that we knew that this really wasn't going to be an issue."