09/10/2007 at 01:00 AM EDT
A hit television show with 14-hour days on set. Seven-month-old twins and a 5-year-old at home. With diapers to change and dialogue to memorize, how does Seattle Grace's hottest surgeon chill out? He straps himself into a souped-up Ford Mustang and whips around a racetrack at speeds of up to 170 mph. "When I finally get to the track, I feel very relaxed," says Dempsey. "It's nice to just shut your mind off and enjoy the experience. It's a great escape."
Not that he has any major complaints about his day job. The success of Grey's Anatomy has allowed Dempsey, 41, the luxury of turning his decade-long racing hobby into a part-time career. He's a driver for Hyper Sport, a Grand Am Road Racing team he co-owns that competes in endurance races lasting up to 24 hours (two drivers switch off). He and his teammates show off their fast moves in a bonus segment on the "Seriously Extended" edition of the Grey's Season 3 DVD set, available Sept. 11. "It's a side of my life I really love," Dempsey says of racing. "Outside of my family, it gives me the most satisfaction."
As with many things in his life, he credits his wife, Jillian, 41, with encouraging him to pursue racing seriously. An avid athlete who skied (and juggled!) competitively as a youth in Portland, Maine, Dempsey traces his interest to watching the Indianapolis 500 with his father as a boy. When he began dating Jillian, he says, she encouraged him to go to racing school. As Hyper Sport co-owner and teammate Joe Foster puts it, "She told him, 'Stop talking about it and just go do it.'"
Dempsey, who enjoys bringing daughter Talula, 5, and sons Darby and Sullivan, 7 months, to the track when he can, was a quick study. From the start, "He showed an aptitude," says Foster. "He's quick, but not too aggressive; there's a good balance there. And he's competitive. He wants to win."
In 2003, Dempsey decided to go pro, buying a team with fellow drivers Foster and Rick Skelton. He gets no superstar treatment during Hyper Sport's 14-race season. "He stays in the same crummy hotels and drives the same crummy rental cars [to the races] says Foster. "If he's not driving his race car well, we get on him." Adds Dempsey, "Some weeks I have great results; some weeks I have horrible results. That's racing."
This has been a good year for Dempsey, who celebrated his career-best finish when he placed sixth in Miami last April. He has slowly built up to being able to drive as fast as 170 mph, a speed Dempsey says doesn't scare him. "If I felt that way, I shouldn't be in the car. I push the limit so that I can find the limit, and then pull back a little."
Plus, the speed is what he's there for. "There's an aggressive calm state that you go into," he says. "Last year was overwhelming with the anticipation of the boys' birth and the dynamics of the show." In the car, he adds, "You can't get too far ahead, and I like that. I love being put in the present."
This season, he should have less work-related stress to exorcise on the track. After last year's upheavals at Grey's, he says, "The humor is back. The mood is one where people are enjoying themselves again." And he plans to take a real break rather than shoot a movie during this year's hiatus. (Last summer, he shot the romantic comedy Made of Honor, due out in 2008.) "I'll take a break to spend time with my family and concentrate on driving. The closer I get, the more I want to compete for a podium finish."
There's just one potential drawback—at least to avid McDreamy fans: helmet hair. Dempsey doesn't sweat it. "My hair is shorter now, so it's not so much to deal with," he says with a laugh. "You put your helmet on and you don't have to worry. Afterward, I just put a hat on."