When the sun sets at 6:50 p.m. on Saturday, Oct. 14, the circadian rhythms that make man primarily a creature of the light will come into play. Thirty minutes later, the green flag will be waved at Charlotte Motor Speedway to start the Bank of America 500, the only night race in the Chase for the NASCAR NEXTEL Cup.

What is it about night racing that makes it so special? That it harkens to the intimacy of the short track where so many drivers cut their teeth? Is racing just more glamorous under the lights? Bruce Springsteen once lyricized that it's "Because the night belongs to lovers," but on this day, the night belongs to the drivers.

Since the introduction of klieg lights in 1940 at harness tracks, horse racing and later automobiles popularized things going fast at night.

"Night brings out an intensity in athletes you simply don't get during the day. Possibly this goes back to primitive man whose greater alertness at night often meant life or death," said H.A. "Humpy" Wheeler, president and general manager of Charlotte Motor Speedway. "Animal behavior is certainly different in the dark. Sharks, tigers, lions and other big cats hunt primarily at night. Ask anyone who has ever hooked a big shark at night if it wasn't a great deal scarier than the same hookup in the daytime.

"I also believe drivers can actually see and focus better on properly lit tracks. That really sounds strange, but the lighting system at Charlotte Motor Speedway produces about 120 foot candles of light on every part of the racing surface," Wheeler added. "This is really bright because many high school baseball or football fields only produce 40 to 60 foot candles.

"With the light concentrated on the racing surface, everything in the background is blacked out and the driver's eyes can focus on the surface itself, which leads to increased racing."

"I am a big fan of running under the lights and I think most of the guys are," said Denny Hamlin, the only rookie in the Chase. "Everything seems more exciting under the lights and that goes for the fans and the drivers. It reminds me of running at the local tracks growing up and that was some of the most fun I have ever had in a race car."

Kevin Harvick concurs, "It's a good ol' Saturday night race under the lights."

Yet the NEXTEL Cup Series only has nine point races at night during the season with all but the Bank of America 500 starting in daylight, which can mean different things for different drivers.

Dr. Bill Thierfelder, a noted sports performance psychologist and former athlete now serving as president of Belmont Abbey College in Belmont, N.C., says for some racing at night may be as simple as adjusting their normal routine by a few hours.

"On most race days, you're used to getting up at a certain time, eating at a certain time, you go check out the car. You have your normal flow of what you do and then it's race time and it all sequences together," Thierfelder explained. "Sometimes when a race is at night and, in a sense delayed, it can be a little challenging for an athlete because you feel like you're waiting."

Scientists have long known that circadian rhythms, linked to the light-dark cycle, are important in determining the sleeping and feeding patterns of all living creatures. They have found clear patterns of brain wave activity, hormone production, cell regeneration and other biological activities linked to this daily cycle.

Thierfelder says a night race potentially creates an artificial situation that can take an athlete out of their normal groove.

"Some people are morning people, others are night owls. There's different theories attributed to that such as circadian rhythm, which is a daily rhythmic activity cycle based on a 24-hour interval. In some ways it may be an advantage for some drivers having it flipped around," Thierfelder added. "This may be a better schedule for them."

One of those drivers appears to be Jimmie Johnson. The driver with the most nocturnal success is one for whom Charlotte couldn't come fast enough. Johnson leads all Chase drivers with five wins after dark over the past five years (36 total night races), quite serendipitously all at Charlotte Motor Speedway. Save for rookie Hamlin, he also has the best average finish of the Chase drivers at night with an average finish of 12.6.

Driving in the dark also bodes well for Matt Kenseth and Dale Earnhardt, Jr.

Of the 10 Chase drivers, Kenseth has the most top-10 finishes at night with 24 followed by Dale Earnhardt Jr. who has 22. The two are tied for the most top-five finishes at night with 14. Kenseth also has three victories and Earnhardt two after dinner time. Both have also won the NASCAR NEXTEL All-Star Challenge non-points event run under the lights at Charlotte Motor Speedway.

Eight of the 10 Chase drivers have wins over the past five years in night races, with only Jeff Burton and Hamlin still waiting to find victory lane.

Like his Hendrick Motorsports teammate, Gordon has excelled under the lights and leads all Chase drivers with four poles at night along with two night wins and 11 top-five finishes over the past five years.

"At night, the track gets cooler, tighter and faster," Wheeler noted. "Some drivers excel on tighter tracks. Earnhardt Jr. is one along with Matt (Kenseth), Ryan (Newman) and Jimmie (Johnson), who might be our best night racer."

Anyone who has worked third shift knows how different the night is both physiologically and psychologically. Starting a race later than normal, brings its own requirements of the participants.

Drivers have to adjust and prepare for night racing. Fatigue affects reaction time, which can be the difference between winning, losing and safety on the track.

Kyle Busch said, "I sleep later. We schedule all of our sponsor appearances later in the day. I usually spend the day relaxing as much as I can.

"I think it's an adrenaline rush. If everything is pushed back a few hours and I get more rest the night before and even during the day it doesn't bother me too much," Busch concluded.

"I used to say I needed an hour of sleep for every 100 miles," noted Hamlin. "But between running both the Cup and Busch series I have found I need a little more these days.

"As far as changing my routine for a night race, I try to keep every weekend the same. I don't ever worry about getting tired before a night race though because the excitement around night races in the Cup series is like nothing else."

Dr. Thierfelder cautions that there is no absolute rule here as the time of day affects all people differently. This can be either an advantage or disadvantage when it comes to visual acuity and depth perception, as well as their normal circadian rhythms and sleep requirements and how that affects reaction time, judgment and endurance.

"One thing about all these dark thoughts is that things are definitely different at night, including the racing," Wheeler said. "It's simply better!"

Tickets are still available to all Bank of America 500 Week events and can be purchased by calling 1-800-455-FANS or online.

Source Contact: Dr. Bill Thierfelder Belmont Abbey College (704) 825-6726