It's the payoff from his intense fitness routine, which on Sunday will include running the Daytona Beach Half Marathon at 6:30 a.m. the same day as Daytona 500 qualifying and hours after the Sprint Unlimited exhibition race.
Johnson will be joined in the field by fellow drivers Michael Waltrip, Kasey Kahne and Aric Almirola in the 13-mile race that starts at the Daytona speedway, includes a stint on the beach and ends at the track.
"I've just really stayed with the training program," Johnson said. "I've always ran but just kind of slow and run long distances. I've worked hard to get some pace. It's probably the best offseason I've had for not gaining weight. I've stayed busy and was able to stay lean even through the holiday."
Johnson was low key at the season-ending awards ceremony in Las Vegas, where he continued training for a triathlon in Palm Springs, Calif., the morning after the banquet. He finished first in his age group, and eighth overall.
He says he's having a hard time scheduling events this year, but is eyeing a triathlon the morning after the August race at Bristol and is trying to work himself up to first a half iron man and then a full iron man competition. Johnson says it's a far cry from NASCAR's early days, when driver partying was legendary.
"Times have changed for sure. I'm not sure anyone would have admitted training in the Alabama Gang or even the Earnhardt Era," said Johnson. "Fortunately for them, the cars weren't strong enough. If you drove the car as hard as you do now each and every lap, it wouldn't make it to the halfway point then.
"But I look at the seats, the seat belts, no headrest, smoking and racing at the same time, and I'm sure there was some moonshine ingested the night before. There are some tough dudes in the day and I have a ton of respect for them."