"I had to train myself how to breathe. There were times I would pass out physically; I was unable to get back into the cockpit," Cruise says.

Tom Cruise told Empire magazine that he breathed in his own carbon dioxide while filming a grueling action set piece for the upcoming “Mission: Impossible – The Final Reckoning.” The sequence finds Cruise’s Ethan Hunt underwater exploring the wreckage of a submarine.

Impossible," releasing in May. In a new interview, he claimed one of the stunts was so intense that he passed out while filming.