Updated

The Coca-Cola 600 is not a 24-hour, around-the-clock race, although sometimes it might seem that way.

The race will start in daylight (6 p.m. ET) and end in darkness about four and one-half hours later. It’s 400 laps around Charlotte Motor Speedway’s 1.5-mile oval surface, and that’s more than enough to test the patience, endurance and bathroom habits of all concerned – not to mention the strength of machines that must run fast for an extended period.

It’s a race that often features 100 miles of drivers “testing” the race surface and opponents at the start, then 100 miles of jockeying for position at the end. In the middle are 400 miles of endurance – and staying out of the way of drivers who might have a wreck or two in mind.

Oddly enough, Matt Kenseth calls it his favorite race of the year.

“We have our first win here (in 2000), so maybe that's part of it,” he said Thursday. “This is the first track that I made my first Nationwide start (1996) at and have more miles here at this track than any other on the circuit. You only race a 600-mile race once a year – Memorial Day weekend.

“Just a lot of different things. The track goes through huge changes. Typically, it's very different in the beginning of the race when the sun is still out. It's usually hot and slick, and then at the end of the race, after four hours of racing or four-and-a-half hours of racing, the track is as fast as it's ever going to be, and everybody picks up a second and it's on. It's like you wait four hours to run a trophy dash. It's just a fun event. A lot goes on. You have to pay attention for a long time and really keep up with the adjustments.”

Brad Keselowski said even though the closing segment of the 600-miler obviously is the most important, the middle portion also can be critical.

“You can’t win the race at mile-marker 300, but you sure as heck can lose it, whether it’s blowing through your pit stop, losing wheel, missing a shift or blowing a tire – anything like that,” he said. “At some point, you have to put yourself in the protection mode and say, ‘Get through this part of the race and not lose it.’ … You have to be able to play defense and play offense. In a long, 600-mile race, essentially it’s your time to play defense.

“Although you can’t win the game, playing defense you can certainly lose it.”

Mike Hembree is NASCAR Editor for SPEED.com and has been covering motorsports for 31 years. He is a six-time winner of the National Motorsports Press Association Writer of the Year Award.