BY ALEXANDER HARO
Vitomir Maricic, a freediver from Croatia, did something incredible on June 14: He held his breath for 29 minutes and three seconds, shattering the previous world record by nearly five minutes.
For context, a bottlenose dolphin can hold its breath for about 8-10 minutes. Not to take away from his achievement, but Maricic did have a bit of a leg up in the form of pure oxygen, which he breathed for 10 minutes before the attempt.
Maricic achieved the record in what essentially looks like a pool set up in a hotel banquet room. You can hear what he has to say about the record in the just-released seven-minute video covering the event, below. It was an incredible achievement.
The science behind holding your breath
But perhaps the most interesting aspect of it all is the breath holding, and the science behind it. There are tiny clusters of cells in the brain and neck called chemoreceptors, which react to the level of carbon dioxide (CO2) and oxygen (O2) in the blood. They’re supposed to maintain the correct balance, and they tell the body when it needs to regulate that balance.
When you’re holding your breath, the CO2 levels rise while oxygen levels drop. Weirdly, though, we actually have quite a bit more time than the body would lead us to believe. After a certain point, the body begins to fire the diaphragm, contracting it involuntarily in a way that you’ve probably felt if you’ve been held under for an uncomfortable amount of time. Usually, an untrained breath holder will listen to that signal and begin to breathe, but you’ve generally got more time before you need to take in air.
But when you huff pure oxygen, as Maricic did before his record attempt, a few things happen. First, that involuntary contraction of the diaphragm is delayed, but there’s no signal of dropping oxygen. The blood is still full of it. It should be noted here that breathing pure oxygen is extremely dangerous and can lead to oxygen toxicity, which can be fatal. Don’t do it unless you’re a competitive freediver under close medical supervision.
“Still, even with 100% O2, CO2 (the primary stimulus for breathing) rises during the breath hold,” explained Anthony Bain, an associate Professor of Kinesiology at the University of Windsor. “However, fortunately for the oxygen-assisted breath holder, elevated blood O2 blunts the chemoreceptor response to CO2. The combined effect of an absent O2 response and a dampened CO2 response allows someone to hold their breath for much longer.”
Already elite
That’s not to say that you or I could hold our breath for half an hour if we breathed pure oxygen. Even without breathing pure oxygen, Maricic can hold his breath for around 10 minutes. He’s a freediving world champion with a wildly impressive competitive record that includes, for some reason, a 240kg squat at a depth of 10 meters.
Maricic explained on Instagram that when he began his dive, he had roughly five times more oxygen in his body than average. He didn’t just do it for the record, though. He wants to raise awareness for ocean conservation via Sea Shepherd’s “Fit for the Ocean” fundraiser. It’s something he’s been deeply invested in for a long time.
The original version of this story first appeared on The Inertia.
