The 30-year-old often indulges in surfing and insists he has feared for his life on a number of occasions.
"I've surfed a couple of times where I've been pinned under a reef and I'm right at the end of my breath, and there's nothing else you want to see more than the surface," Hemsworth said in a statement.
Talking about his experience on the Formula one track, he said: "It's the near misses that you don't see when you're walking down the street, then later you think, 'S**t, that bus was two inches away from hitting me."
"There were moments when driving on the track where you think, 'I better pull back here', because you think of how things could end up," he added.
Directed by Ron Howard, "Rush" is a biopic based on the 1976 Formula One season and the rivalry between Hunt and Niki Lauda.
Slated to release Friday, the movie also features actors Daniel Bruhl and Olivia Wilde.