Now that he's tested the human body's lung capacity, what will he put himself through next? David reveals that he'd like to try to claim the world record for staying awake the longest. The current record is 11 and a half days. "So 11.57 days would be a million seconds," he says.
When David encased himself in an ice block in 2000, he says the cold was not the most difficult thing to endure. It was the sleep deprivation that nearly drove him mad. "It was the most difficult endurance thing that I'd ever played with, and I was always kind of afraid of it," he says. "I think after three or four days without sleep ... I was hallucinating, so it was a beautiful and a crazy and intense experience, but it was also scary to not have control."