Why NASCAR’s Jimmie Johnson Is Leaving His Lucky Boxers at Home

Jimmie Johnson gets nauseous in a car.

Not when he’s driving 190 mph around the track for 4 hours, but when someone else is in the driver’s seat.

"I get motion sickness," said the 38-year-old racing great as he revealed perhaps his one and only motor vehicle weakness during an interview at the Daytona International Speedway.

The racing season is just beginning and Johnson is on the edge of tying the greats, Dale Earnhardt Sr. and Richard Petty, holders of seven NASCAR championships. But before the race and the season’s business gets underway, he shared a little about himself – what makes him feel guilty, why he’s in the gym six days a week and what he thinks about his wife’s driving ability.

For five consecutive years, beginning in 2006, Johnson snagged the Championship Cup in the NASCAR Sprint Cup Series, with his iconic No. 48 Lowe’s car, getting rock star treatment from an exploding fan base, and millions of dollars in endorsements. And with each victory was a growing expectation that he could smash any record. But instead, Tony Stewart snapped the streak, and oddly enough, Johnson had a slight sigh of relief.

"There was a huge weight that was lifted, when we lost out in 2011. I didn’t realize how much pressure there was to continue," he said.

But since Johnson and his team won the cup back in 2013, he’s sitting atop a pile of six championships, and within reach of tying legends Earnhardt and Petty. Which is why the Daytona 500, the "Great American Race," is more than just the start of the racing season, it’s the start of a quest.

"I don’t feel pressure from the fans or supporters, but from the inside, from our team," said Johnson.

But he knows the fans are there, and he’s thankful for them, even if he can’t say it himself. During race days, Johnson has a packed schedule – interviews, meetings, training – there’s just not that much time to meet and greet the people that support him. And that weighs on him.

"That’s one thing I do feel a little guilty about, sometimes," said Johnson. "I don’t get the whole experience of saying hello or signing (autographs). But I think the true fans, the ones that really support us, really understand that this is our workplace."

And like everyone else, he likes to spend a little time away from the office, chasing other goals. A week before the Daytona 500, Johnson completed a half-marathon in 1 hour, 28 minutes; an impressive payoff for all the training he puts himself through. He’s already got a few triathlons to his name, and is hoping to add a few more competitions.

"I’m training six days a week: running, biking, swimming. You have to put the time in to get the physical part of racing," he said.

For a guy that seems to thrive on challenges there is one obstacle that he’s avoiding for the sake of marital bliss. With a little hesitation, he answered a question about whether he’s behind the wheel when he’s out with his wife and their two daughters.

"My wife grew up in Oklahoma, is very capable of driving," said Johnson. "But she was in New York for years and years and years, and can hook us up on the subway, and hail cabs and all that, but she went years without driving a car, so she lost a little bit, there."

This, coming from a guy that can’t hold his lunch from the passenger’s seat.

ABC News' Mary-Rose Abraham and Brian Fudge contributed to this episode.