In February 2010, Peter Colat, a Swiss freediver, broke the world record for holding breath when he held his breath underwater for 19 minutes and 21 seconds. Colat, 38, performed the feat in a water tank in St Gallen, Switzerland. The previous Guinness World Record for oxygen-assisted static apnea was 19 seconds shorter and was set by an Italian, Nicola Putignano in July, 2009. Under the Guinness rules he was allowed to inhale pure oxygen 10 minutes prior to his attempt.
To fight those powerful instincts to breathe, 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.
Sources: Discovery News, The Telegraph