Jenson Button finishes in top 20 on NASCAR debut despite heat exhaustion

The former F1 world champion, 43, said he feared fainting while driving his Ford Mustang during the 68-lap race at the Circuit of Americas in Texas on Sunday.

"Finished 18th after almost stopping because I had heat exhaustion. It was so hot. I don't have a fan in my seat, which really didn't help me too much," Button said.

"I stopped twice for a minute. They put ice on me, gave me loads of water, and I went back out.

"I was so close to getting out of the car because I thought I was going to faint. I must have drank eight (or) nine bottles of water during the race.

"The team kept me calm, and it's the reason why we got a good result in the end. So, I was happy."

Button will next compete in the inaugural Chicago Street Race on July 2 before racing at the Indianapolis Motor Speedway road course on August 13.