He lasted all of six seconds.
When he spoke again, he said it was torture. He told Keith Olbermann, "I was willing to prove, and ready to prove, that this was a joke, and I was wrong. It was horrific. It was instantaneous. And look, I felt the effects for two days."
Olbermann donated $10,000 to a support group for veterans in return for Muller going through with the waterboarding.
See for yourself http://www.huffingtonpost.com/2009/05/26/olbermann-mancow-intervie_n_207963.html