NASCAR driver Carl Edwards celebrates his victory with a backflip. Edwards, considered by some the biggest physical fitness fanatic in auto racing, won the Dodge Dealers 400 last Sunday in Dover, Del. He will compete in this Sunday's LifeLock 400 at Kansas Speedway.

Smoking, drinking, womanizing daredevil. Such was the image of a race-car driver way back when.

“David Pearson had a cigarette lighter in his car,” ESPN analyst Dr. Jerry Punch remembered. “Dick Trickle, you never saw him without a cup of coffee in one hand and a cigarette in the other.”

Football players wear face masks now, hockey players helmets. Safety standards change in sports, usually for the better.

“Most of them have pretty rigorous workout routines now,” said Punch, in town this weekend for the LifeLock 400, a Nextel Cup event at Kansas Speedway. “Full-time trainers. Gyms in the house. Most of the race shops have sophisticated gyms with full-time trainers for their over-the-wall crews, as well as the drivers. Most of the drivers take about a half a day a week off, with their families Monday, to relax, kick back and have some mental health time. A lot of them will play golf that day to do something active to get a lot of the soreness out of their bodies.”

That’s about it for leisure.

Punch told a story about former heavyweight champion Smokin’ Joe Frazier to illustrate the physical demands of driving a race car.

“From his earlobes down to his shoulders he was one big triangle of muscle,” Punch said. “They put an extra seat in Bobby Allison’s car for him. Bobby Allison looked like he should be delivering papers, skinny little kid. Joe had trouble holding his head up, and he was out of breath because his heart was working so hard.”

Physics, not fear, makes the heart race, Punch explained.

“The biggest strain on the body is the cardio-vascular strain,” Punch said. “What happens is, depending on what race track a driver is on, you’re going to experience different G-forces (gravitational pulls) as you go through the corner. … Drivers can experience three, four, five Gs, depending upon the tire gripping the car’s got, and how well the car’s dialed in. Sometimes the better the car’s dialed in on the racetrack and the better grip you get in the corner, the more punishment the driver takes in the seat.”

What happens when a driver goes into the corner and the G-force goes up?

“Let’s say for three Gs, suddenly, your head, instead of weighing eight pounds, weighs 24 pounds,” Punch said. “And you’re having to hold that head up for 300 laps or 500 laps or 400 laps, depending upon the track. Your neck muscles just wear out.”

And the heart speeds up.

“The G-force pulls down so much it reduces your cardiac output, how much blood your heart can pump in a single pump,” Punch said. “So in order to make up for that your heart has to speed up, so every time you go in a corner and experience that G-loading, your heart rate speeds up. … That’s why a lot of these drivers relate what they do to almost like running a marathon where they’re constantly having to deal with the cardiovascular stress and strain on their system, on top of which they have to physically be able to hold onto the steering wheel and hold their head up. They have remarkable endurance.”

Heat inside the car is another factor that places endurance demands on drivers.

At a recent race, Punch said, temperatures inside the cars reached 135 degrees.

“When we interviewed drivers after the race they were so out of breath when they climbed out of the car they could hardly answer questions,” Punch said. “We go to Carl Edwards, he’s fresh as a daisy and looked like he could race 400 more laps.”

Edwards, from Columbia, Mo., sometimes is cited as the biggest physical fitness fanatic in the sport.

Punch said friends he has made covering other sports, such as college basketball and football, attend a race for the first time and marvel at the physical and mental demands placed on the drivers.

“This year’s race at Charlotte lasted four hours and 36 minutes,” Punch said. “That’s one-and-a-half football games, and there’s no halftime. You may have a caution flag, but you’re still in the car, still in the oven, don’t get to take your helmet off, still sitting there when it’s 135 degrees, still breathing the fumes, still have to focus and concentrate. You can’t run to the sidelines in between plays. There are no timeouts. There’s no halftime to go to the locker room to get something to drink to cool off. There are no TV timeouts. It’s just a constant three, three-and-a-half hour endurance test they go through each week.”

The demands for speed and strength on crew members are so great, they also undergo intense workout routines, according to Punch.

“These guys who go over the wall not only have physical trainers … one team brought in a ballet instructor because they wanted lightness on your feet, the ability to move and pivot in a hurry. And most of these guys have aerobic instructors. Many of these guys are former NFL or college football players. … Now they carry a jack and go over the wall.”