Author and journalist Christopher Hitchens says it was difficult finding someone who would agree to waterboard a man of 60. (Christian Witkin/McClelland & Stewart)

Christopher Hitchens, a Washington-based journalist known for his support of the Iraq war and the U.S. war on terror, has subjected himself to waterboarding.

The experiment was done in answer to critics who challenged him to try it after he defended U.S. treatment of Muslim prisoners.

The controversial interrogation technique, which simulates drowning, is the focus of an intense debate in U.S. political circles.

Washington has been divided over whether or not waterboarding can be called torture since it was learned the technique was used by the CIA on at least three detainees, one of them being Khalid Sheik Mohammed, who is accused of plotting the Sept. 11 attacks.

The experience left Hitchens with no doubts. The August issue of Vanity Fair will carry his article titled "Believe Me, It's Torture."

Hitchens told CBC News he decided waterboarding was torture while talking with U.S. forces specialists about it after the experience.

He'd lasted, he estimated, less than 10 seconds under the technique. "I would defy anyone to stand more — people with better lungs than me and people who are younger," he said in an interview Monday.

"I'm nearly 60 — which actually made it difficult to get this done because people who were capable of doing it said they wouldn't because at my age it could kill me."

Hitchens went into the experience with a code word he could shout and an agreed-upon physical signal which would let the specialists know he'd had enough.

But he said the experience was still terrifying.

"I was suddenly grabbed from behind and pinioned and a hood pulled over my head, a sort of balaclava helmet. It admitted some light but I couldn't really see," he said. "I was turned around a few times I think to disorient me so I didn't know which direction I was facing."

He was then taken to a shed with strobe lights flashing and metallic music playing.

"With my hands handcuffed to a belt, I then had my arms very tightly wrapped close to my torso so I couldn't move anything above my waist and then the same was done to my legs. I was placed on a board which was a shallow incline, but one that put my head below the level of my heart."

Hitchens said he couldn't move at all.

"Then two or three levels of towel were placed on the outside of my face so I was completely oblivious to the outside world, couldn't hear or see anything and was wondering how I was going to carry on breathing … and then water began coming through the towel into my nostril and that was the situation."

A wet hand was also held over his face and breathing in caused the wet towel to cover his nose.

"It had the effect very rapidly of inducing a panic and gag reflex," Hitchens said. "It's almost impossible to avoid doing that, even though … you have some idea of what's coming and what's going on, your system overrides your brain in a sense and all you want to do is make sure you're not breathing water."

The experience has had after-effects — including bad dreams and a feeling of panic that returns whenever he is breathless, he said.

In an article last year in Slate, Hitchens attempted to draw a distinction between what he called techniques of "extreme interrogation" and "outright torture."

But his Vanity Fair article makes no such distinction.

Coming from a writer who has been a strong defender of the U.S. conduct in Iraq and against Muslim prisoners, Hitchens's experience has attracted attention in Washington.

"I can only judge from the reactions I've had so far, including from some people who are supporters of the administration in general on the war on terror who say they agree with me that it's not something that the U.S. should be doing to its prisoners," Hitchens said.

There is "a feeling a line has been crossed, that we're using methods we would have condemned if they were used by an enemy," he added.