There is a lot to adjust to when making the jump to the NASCAR Sprint Cup Series as a rookie driver. Heavier cars, more horsepower, one of the largest stages in all of sports, not to mention the lengthier race distances.

However, there is no longer race than Sunday's 600-mile event at Charlotte Motor Speedway. None of the seven rookies entered in the Coca-Cola 600have ever even completed a 500-mile race at the 1.5-mile track. Yet on Sunday, they'll not only attempt to hit the 500-mile mark, but then race another 100 miles to the finish.

While the task at hand will be a challenge, the mental and physical preparation started some time ago.

Justin Allgaier, who sat out last weekend's Sprint All-Star events, has mainly focused on cardio, running and doing more activities outside in the heat. But he has also pulled out an old-school racing trick.

"It's amazing how hot it is inside these cars," Allgaier said. "That's more of it than the physical side. When you get done with a race, your muscles aren't sore. You're just so hot and exhausted because of the heat.

"I heard a long time ago ... they used to drive around in the summer with their windows up and the heater on," he said, channeling NASCAR Hall of Famer Bobby Allison. "I tried that when I was younger, and it actually works. You're going to be miserable when you're doing it, and you better not be going anywhere, because you're going to be sweating like crazy. But it's amazing what the heat training is and how important it is to making it 600 miles."

While Allgaier took the serious approach to prepare for Sunday's 600-mile endurance race, fellow rookie Alex Bowman had a little fun with his training.

"I've been eating a bunch of them Krispy Kreme sliders back there and the baconator funnel cake," a smiling Bowman said of some of the unique food fare offered this year at CMS concession stands. "I think all of us have done a pretty good job at the gym and working out. It's going to be tough. I get out of a 500-mile race and I'm like, 'Man, I was in there forever.' So, 600 miles will be a whole other ball game. I'm looking forward to the challenge."

As someone that races at any chance possible, Kyle Larson joked he had been working out his bladder to make it the extra length of the race inside that car.

"Yeah, I've been working my bladder out, trying to increase the size so I don't have to go pee," he said with a smile. "That's about it."

While the rookies may be the most inexperienced for Sunday's class endurance race, the Coca-Cola 600 has seen its share of rookie winners.

Jeff Gordon earned the first of his 89 wins during his rookie season in the 1993 Coca-Cola 600, while Matt Kenseth took the checkered flag as a rookie in 2000.

"It's a really big event for rookies," Larson's teammate Jamie McMurray said. "That's what I was telling Kyle, 'That this could be a big weekend for you.' This is a weekend where rookies win races. So I think that's really cool for Kyle."

Whether it's Larson or the other six rookies entered in the field, Sunday's Coca-Cola 600 will be a true test unlike any other they've faced before.