It has become auto racing's Memorial Day Weekend Triathalon: Race 500 miles at Indianapolis, hop on a helicopter that whisks you to a waiting jet, fly 90 minutes to Charlotte, hop on another helicopter to get to Lowe's Motor Speedway, and wrap up your day with a 600-mile sprint in the Coca-Cola 600.

It has become, without a doubt, the most exhausting and demanding day of racing for any driver, short of running the full 24-Hours of Daytona by yourself (which no driver ever does, anyway).

	Robby Gordon competed in both the Indy 500 and Coca-Cola 600 in 1997.

Racing both at Indianapolis and Charlotte on the same day has become a badge of distinction that few race drivers can proudly say they wear. In fact, only three drivers have accomplished the dual driving feat: John Andretti, who became the first driver to do so in 1994 (finished 10th at Indy and 36th at Charlotte), Robby Gordon (1997, finished 29th at Indy and 41st at Charlotte) and Tony Stewart (1999, finished 9th at Indy and 4th at Charlotte).

Stewart will attempt the Indy-Charlotte connection for the second time in his career this Sunday. And while some may say the second time is usually easier, it has been anything but for Stewart, who has approached this year's back-to-back racing in a much more determined, studious, calculated and determined point of view than he did two years ago.

When Stewart raced in both Indianapolis and Charlotte on the same day in 1999, he did it for the sport and the adventure of it. Little did he realize the physical demands and toll that day would take on his body.

This year is different. Stewart has trained for both races like a person who truly would be taking part in a marathon. He's been very careful about what he has been eating, has a personal trainer to get his body in shape to drive 1,100 miles in roughly seven hours, has curtailed his partying and off-track activities.

In so doing, we've seen a side of Stewart rarely seen before. He's become a man of conviction, dedication and determination. And given all those traits, he could very easily win one or even both races on Sunday if Lady Luck shines upon him.

ESPN.com talked with Andretti and Gordon to get their thoughts on Stewart's round-robin exploits this coming Sunday, the types of things they endured when they tried to do the back-to-back events, as well as any advice they might be able to give to Stewart.

Here are their thoughts:

ESPN: How difficult of a task is racing at both Indianapolis and Charlotte on the same day?

ANDRETTI: "The difficulty of the task is based on anxiety placed upon emotions of the weather and other things that are out of your control. The things that are in your control are just driving the race car and doing your job. From that standpoint, and from everything I hear, Tony is more aggressive at making sure he's ready for the (Coca-Cola) 600, especially.

He had a good race at Indy, came down and had a great race at the 600 (in 1999). I don't know if he would have been able to do any better, but I think it's always better to get out of a race car and feel good. I know that with me, when I did it, when I got on the airplane the doctors shoved an IV (intravenous tube) in me.

You have to remember that even after finishing at Indianapolis and you might feel great, you haven't drank anything in well over a couple hours; you've been working. You're going to lose some hydration, and that's the critical thing. The thing now for Tony is the 600 has been moved, not as early as when I did it, but pretty close to it. As a result, the pressure is higher based on weather. Tony's doing it for the same reason I did it, because he wanted to race Indy."

ESPN: What's the most important thing that Stewart will have to keep in mind Sunday?

GORDON: "The most important thing is having everything organized and even cover the 'what if,' and that's really, really tough. If Tony doesn't have to worry about anything but someone holding his hand from the time he gets out of his Indy car, he needs to get an IV, needs to get in his airplane and fly, and hopefully he'll take a nap. Just that hour, 15-minute rest period, because you concentrate so hard at the Indy 500. It's not very physical, but for 500 miles, for 2 1/2 hours, it's knife-edge, you're right there on that ragged line, and you've got cars around you.

Indianapolis is very hard on the brain. I think an IV, sleep and a good plan for all the scenarios. I've been fortunate to do it now twice, and John's done it once. But Tony is a great race car driver. I don't think I can compare myself to him today because I haven't had the tools in Winston Cup, but both of us showed up here at Indianapolis, and I hadn't sat in an Indy car for one year and he hadn't sat in one for two years, and we qualified in the top-10, both of us."

ESPN: Why was it important for you to become the first driver to do both races in the same day?

ANDRETTI: "I think the motivation is because it's there. And, I wasn't really a stock car driver back then. I was more of an Indy car driver at that point. I didn't want to pass up on the Indianapolis 500. At the end of that year, I was told by the people I was signing up with that if they ran another car at Indianapolis, that it would be OK if I did it. I took their word for it, but when the time came, they backed out. So that was two years lost that I didn't run Indy. And because those two years were lost, the momentum was lost as far as the next group of people I talked with.

For us, we grew up open wheel race cars, and the Indianapolis 500 is a race that you have to have in your resume to feel like you've accomplished something as a driver. If you win the Indianapolis 500, it doesn't matter if you won all the sprint car and midget car races, which are important to do to get yourself there, but if you win the Indy 500, you're like at the top of the mountain. You're immortalized, you're an open wheel champion forever, because they don't call it the Indianapolis 500 winner, they call you the Indianapolis 500 champion."

ESPN: Because you're running two of the biggest races around, is it by far the most tiring day any driver can have, not just the miles involved, but the stress, the physical exhaustion, etc. Is there any other race that would compare to that at all?

GORDON: "Baja. The more you do stuff like this, the more you get immune to it. Tony's raced some long races this year in stock cars. It's not too physical, it's mental, but it's physical as well because it's hot and sweaty. In stock cars, you move your arms a lot. In Indy car, it's a fighter plane. It reminds me so much of a fighter pilot, everything is a precise move."

ESPN: What's the big difference going from driving an open wheel car to a stock car within a few hours of each other?

ANDRETTI: "It's really no different than hopping from a go-kart to a Top Fuel dragster. You know what you're in and you know what you're doing with it. It's like a natural thing; you don't sit down and think about it. It's just a natural feel you have when you're in a car. It's like when you're going into a corner and lifting: you know you have to lift. It's not because you say you're in a stock car now. From the standpoint of jumping from one to the other, even guys who do Busch and then Cup cars, there's probably more of a likelihood doing those than going to Indianapolis, doing the 500, and then coming down to Charlotte to do the 600.

The main thing is to make the distance and wind up finishing the 600 as if you didn't do Indianapolis earlier the same day. That's almost impossible because Indianapolis, from an Indy car standpoint, is not a real physical race, but it's mentally draining. You always have to be on top of your game because you're covering so much ground, so quickly, that you can't miss one little thing because that one little thing might send you into the wall. In a stock car, if you lose the back end and save it, you go on. In an Indy car, you might get one or two opportunities in a race to do that, but if you're not on your game, it's tough to get up and win it and not trip too many times due to the mental part of it."

GORDON: "Both tracks are oval, and you still do the same thing to correct the car, but I think the cars are so different, you might as well race on dirt, they're so different."

ESPN: To follow that up, because of the speed difference between Indianapolis and Charlotte -- you're hitting close to 230 mph at Indy, and a top speed of maybe 180 at Charlotte -- there's the perception that going from racing at Indianapolis to racing at Charlotte is like going from driving on the Autobahn to driving on a city street. Do you agree with that logic and can you perceive the speed difference when you're behind the wheel?

GORDON: "There definitely is a speed difference, for sure, but other things come into play. Sure, the speed goes down when you're in a stock car, but now the cars run six inches apart. So, your precise factor, forward and back, and you've got to slice yourself into a nice little hole. Forty-three cars on the racetrack is a lot of cars. Tony has his work cut for him, it's a tough chore. I wish him a lot of luck, but not too much luck at the speedway because I could use a little luck there myself."

ESPN: If another opportunity arose to do both Indianapolis and Charlotte in the same day, would you do it?

ANDRETTI: "I'm not going to say that because Michael (his cousin, Michael Andretti) is back in the 500 that my interest is raised up again, because I've always been interested in the 500. I've talked with Kyle (Petty Enterprises team president Kyle Petty) and he understands. I certainly don't want to do it if the King (team chairman Richard Petty) is dead-set against it. That's not my goal, to destroy something they're trying to build.

They're interested in John Andretti, but they're interested in the bigger Petty Enterprises. I understand that, and that's what it's all about. There's a lot of people at Petty Enterprises that are depending upon me to show up.

It's more than getting just one person behind me, it's getting everybody on the team to know and support that this is what I'm going to do. In a way, it's sort of selfish because you're doing it because you want to do it, and no way are they gaining a benefit from it, so it's difficult."

ESPN: When was the last time you drove an Indy car?

ANDRETTI: "That race (1994 Indianapolis 500)."

ESPN: Do you miss the open wheel style?

ANDRETTI: "I'll tell you, I miss it all. Now that I'm not drag racing, I miss the drag racing, and I didn't do it that much. I miss the sprint cars, the midgets, the Indy cars. The thing I really miss the most, and I think I have two or three other (Winston Cup drivers) with me on this, if we could run the Silver Crown cars every weekend, then I would be completely satisfied.

That's what I miss the most, I really enjoy the Silver Crown cars. But, I enjoy every type of racing I'm doing. If I wasn't doing stock cars and went back to Indy cars full-time, then I'd miss the stock cars. I've enjoyed every type of racing I've ever done."

Jerry Bonkowski covers NASCAR for ESPN.com.