"A Swiss freediver held his breath underwater for 19 minutes and 21 seconds, according to news reports this week. The gasp-inducing feat beat the previous world record by 19 seconds, and blew away the record of 17 minutes and four seconds that magician David Blaine set on Oprah Winfrey's talk show in 2008....To fight those powerful instincts, a competitive breath-holder starts by hyperventilating for as much as 10 minutes while breathing from a tank of 100 percent oxygen. Breathing hard and fast expels carbon dioxide from the body, buying time before CO2 levels get too high. Likewise, boosting oxygen stores with pure oxygen buys time before O2 levels fall too low. After hyperventilating, if a person isn't unconscious, he'll probably feel dizzy and have extreme cramping in the arms and legs. The next step is to plunge into a tank of water. That triggers a primitive, mammalian reaction called the diving reflex. When confronted with water, especially cold water, the body shunts circulation from the rest of the body to the heart and brain. The reflex, which even chickens have, probably helps babies survive the trip through the birth canal, Lundgren said. By lowering how much total oxygen the body is using, the diving reflex also allows people to hold their breaths for longer stretches. The record for breath-holding on land is around 10 minutes, said Lundgren, who can go eight or nine minutes without breathing. The new record-holder, named Peter Colat, was able to last twice as long because he was in a tank of water. " - bob

I can do 19 seconds... oh, wait... - Paul Buchheit

The TED Talk on this by Blaine was a great watch imo: http://www.youtube.com/watch... - Isaac Hepworth