Seven-time NASCAR champion Jimmie Johnson is accustomed to racking up thousands of miles per season in his No. 48 car. But doing 26.2 miles in a pair of sneakers is a different story.

Johnson completed last month’s Boston Marathon in three hours, nine minutes, and seven seconds, averaging seven minutes and 12 seconds per mile -- two days after he finished 12th in the Toyota Owners 400.

Fitness has been a key to Johnson’s success. With cars approaching 200 mph, and in-car temperatures reaching 130 degrees, drivers need to be in shape.

“I get in a rhythm when I’m training well, eating well, and resting well,” Johnson said Wednesday, four days before the Gander RV 400 at Dover International Speedway, in Delaware. “If I get lazy, it triggers all the opposite things to happen. We need to be fit to race and be out there week after week, so [exercise] is a must.”

Running, biking, and other outdoor activities give Johnson a chance to prepare for the intensity on race days and to improve his mental state. He said that fitness makes him a better person off the track with his family and allows him to focus on the track.

“It’s amazing to me over the course of a season how well training helps me stay in the zone,” Johnson said. “It’s another way for me to work on my mental strength.”

Johnson hasn’t won a race since June 2017, when he captured the checkered flag at the Speedway to tie Cale Yarborough for sixth on the all-time win list with 83. He went winless last season for the first time in his 17-year career.

As the track celebrates its 50th anniversary, Johnson will try build on his success there. With 11 victories in 34 starts at the Speedway, Johnson is its winningest driver.

“I’m so glad it’s on the schedule. It’s my favorite race track,” Johnson said. “I fell in love with it in 1999, in my first year driving it in a lower-division stock car. There isn’t another track out there like it.”

Even with five top-10 finishes in 11 races this season, Johnson sits at 16th in the Monster Energy NASCAR Cup Series standings. He is looking at Sunday’s race as an opportunity to get back on track and to climb in the standings.

“Take a fast car to my favorite track," Johnson said, "and I’ve got a chance.”