The answer: It depends on the rules.
As the Daily Mail explains, humans set breath-holding records in water because they “can hold their breath twice as long underwater they can on land.” The reason: the “diving reflex,” in which the body slows its heart rate and metabolism in order to conserve oxygen and energy when submerged in cold water. The pulse rate in an untrained diver, the Daily Mail says, will decrease 10 to 30 percent when underwater. But professional divers can reduce theirs by more than 50 percent.
Which brings us to records. The event in question—holding one’s breath underwater for as long as possible without moving—is officially called “static apnea,” and there are two ways static apnea records are kept: for dives performed after breathing in pure oxygen, and for dives performed without pure oxygen.
The Guinness Book of World Records allows divers to hyperventilate for up to 30 minutes with pure oxygen before they submerge for their record attempt. This practice, Discovery News reports, helps the body expel carbon dioxide, buying time before carbon dioxide levels become toxic. Boosting oxygen stores, on the other hand, buys time before oxygen levels fall too low, which leads to brain and tissue damage.
In 2012, German freediver Tom Sietas held his breath underwater for 22 minutes and 22 seconds, besting Dane Stig Severinsen’s previous Guinness record by 22 seconds. (Although Guinness still lists Severinsen as the record holder, stating he hyperventilated with oxygen before his attempt for 19 minutes and 30 seconds.) The women’s record is 18 minutes, 32.59 seconds, set by Brazillian Karoline Meyer in 2009. Prior to the attempt, she hyperventilated with oxygen for 24 minutes.
The International Association for the Development of Apnea, which records all freediving world records, does not allow the use of pure oxygen before a static apnea attempt. The current non-oxygen aided records stand at 11 minutes, 35 seconds for men (Stéphane Mifsud, 2009) and 8 minutes, 23 seconds for women (Natalia Molchanova, 2011).
Severinsen has said that he hasn’t suffered any brain damage from his breath-holding record attempts. Still, Discovery News notes, “studies of freedivers have turned up abnormalities in brain scans and markers that suggest brain damage. No one knows what the long-term consequences will be of feats like these.”
Wonder what a static apnea record-setting attempt looks like? Check out this Discovery video of Severinson’s 22 minute breath hold: