That, and the pitstops, will make for an agonising experience in Sepang where track temperatures regularly exceed 40 degrees Celsius -- the cockpit can reach 50 degrees -- and humidity can reach 90 percent.

For an hour and a half on Sunday afternoon there will be nowhere to hide. Anything that slows a driver down, such as the safety car, merely piles on the pain.

"You want a very fast race, no safety cars and just get it over and done with," says Williams' Australian Mark Webber [Images], who has yet to finish a race at Sepang in three attempts.

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"When you stop for a pitstop you might think that's nice but it's just the worst thing you can do because of the heat, there's so much heat around the pitstops.

"When you're behind the safety car as well it can be extremely hot."

At other circuits, particularly in Europe, roaring down the straights allows a driver the time to gather composure and cool down.

Bahrain, an addition to the calendar last year, and this season's newcomer Turkey are also hot races but neither have the humidity factor.

"There's no escape, it's just the heat. Your chest, your head, how hot everything gets. You're just screaming for something a bit cooler from somewhere but there is no place to hide," said Webber.

WATER PROBLEM

In Malaysia, heat fatigue and dehydration are real dangers.

"This is the only circuit where you drive and you can feel the hot air coming into the helmet, it's really strange," said Briton Jenson Button [Images], who took the first podium of his career for BAR in Malaysia last year.

"It makes it quite difficult to breathe.

"It's the only circuit where you feel that you could be getting a sun tan through your suit. You can feel the heat through your suit."

Drivers can lose up to four litres of fluid during the race and a malfunctioning water bottle can have as much impact on performance as anything mechanical.

Two years ago, Button's did not work and it is not an experience he does not want to repeat.

"I lost my water bottle and just couldn't get any drink at all. I was so wet I started shivering for the last 20 laps of the race, it was pretty scary," he said. "Then your vision starts going after that, you dehydrate."

Even when there is a steady supply of fluid, there is not a lot of comfort.

"The problem is keeping it cold," said Button. "It's like drinking tea after three laps. You get past the cool bit which is in the pipe and then it's boiling water."

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