Gothamist Health learned somewhere along the way that smoking one cigaretteis as likely to give you lung cancer as is 4 days of breathing New York City air. That's almost enough to make one want to hold their breath while walking down Broadway. It also makes David Blaine'slatest stunt sound a bit less insane (but not much). As we know, the modest, T-shirt clad street magician is back and has been gracing the Upper West Side with a new feat, spending an entire week under water...only to attempt to break the world record for holding his breath (which currently stands at 8 minutes 58 seconds) while freeing himself from 150 pounds of chains after the week is up. How will he pull off this Houdini-esque stunt without the proverbial smoke and mirrors? Apparently by using sound medical and physiologic reasoning: In an attempt to lower his body's metabolic demands (and thus his oxygen requirement), he has shed about 50 pounds over the past few months. Blaine also plans on meditating to relax, another way to lower his body's O2 needs.

So what are some other ways to help hold your breath? Freediving experts use "gulping," which is a way to suck in a few last breaths of air after you take your largest inspiration. The cynics at the British Freediving Association so guess that he'll probably pull off the trick by breathing in pure oxygen via a tube before stopping breathing. Pure oxygen contains, well, 100% oxygen as opposed to normal air which contains 21% oxygen. This is a method routinely used by some freedivers who have reportedly held their breath for up to 15 minutes at a time. So if you're free on May 8th, stop by Lincoln Center and see the man in the bubble and be sure to wish him good luck while you take in a deep breath of good old City air (or take a drag on your one cigarette). and check out his wrinkly hands, if he's not sleeping.

And David Blaine's "people" are keeping a journal of his stunt for him.