PHOENIX -- A smile lit up Sean McDermott's face Tuesday at the NFL owners meetings when a reporter at the AFC coaches' breakfast reminded the Buffalo Bills' coach of mixed martial arts training that was part of the routine when he served as the Carolina Panthers' defensive coordinator.

McDermott, an accomplished high school wrestler, explained that he adopted MMA training as a way to stay in shape and save his knees from the rigors of running. McDermott sparred in the team's weight room as early as 4 or 5 a.m., drawing jokes from arriving players as their coach got his "butt kicked" by the MMA expert invited by the team.

It was the sort of anecdote that has become commonplace as McDermott settles into his third month as the Bills' coach since being hired in January. From owner Terry Pegula to McDermott's former coaches and players, the message has been made clear: McDermott is a grinder who puts in long hours and studies the game closely.

So when exactly does the man sleep?

"I don't always sleep," McDermott said Tuesday with a chuckle. "Whatever it takes to do some rest and do my job."

But let's say McDermott decides to sleep. When does his alarm clock go off?

"Somewhere between 3 and 5 [a.m.]," he said. "Somewhere in there."

In Carolina, McDermott often joined a group of Panthers players who called themselves the 'breakfast club' for their early-morning workout hours. That allowed McDermott to connect with breakfast club members such as fullback Mike Tolbert, who signed with the Bills in the opening days of free agency.

McDermott acknowledged Tuesday that rest and work-life balance are important, especially when organizational decisions he will make as head coach require clear thinking. But in his initial weeks and months as an NFL coach, there has been little time for anything else -- so much that one of his mentors, Chiefs coach Andy Reid, joked that McDermott will need to schedule time to use the restroom during each day.

"I'm so focused on what we're doing right now at One Bills Drive that all I honestly know is how to get my car to our apartment to that stadium," McDermott said Tuesday. "Anything else around that, I have a hard time figuring out in Buffalo itself."