Free divers are constantly pushing the limits of the human body, diving ever deeper beneath the ocean’s surface every year. New Zealander William Trubridge has now gone deeper than any unassisted free diver before by breaking his own world record – twice. In less than 72 hours.

Trubridge plunged 122 meters (400.2 feet) below the Bahamas’ crystal blue waves on April 30, and then surpassed that mark by two more meters (for a final 407 feet) on May 2. He dove at Dean’s Blue Hole during the annual Vertical Blue competition, surrounded by family, a safety team and onlookers.

Before his dive on Saturday, he lay on his back, eyes toward the sky, his lungs sucking in as much air as they could hold. He flipped over and disappeared under the water.

Around 30 feet, his lungs shrunk to half their normal size as the air inside them contracted. At 40, he hit the so-called “doorway to the deep,” and the ocean ceased its upward, buoyant pull.

Nearing 100 feet below the surface, triple the normal amount of pressure pushed against Trubridge’s body. His heart rate slowed, and he passed the 115-foot mark – a depth from which champion free diver Natalia Molchanova never returned during a recreational dive in 2015. Past 230 feet, the depth that ended up killing diver Nicholas Mevoli at the exact same diving spot in 2013.

He continued, with hands on a cable as the light reflecting through the waves dimmed to darkness. Around 300 feet, his chest collapsed to half its normal size and blood and water flooded his thoracic cavity.

Trubridge had hit this depth before. Before these dives, he had won 15 world records, each one pushing deeper and deeper below 300 feet. He continued.

At about 400 feet, he grabbed for the 122-meter tag.

“I took my tag and tried to attach it to the velcro on my leg, and for some reason it wouldn’t attach,” he said. After multiple attempts and precious wasted seconds, he got it to stick.

“I was a little concerned,” he disclosed in a video account of his dive. But he reached his safety team, and then made it to the surface. He’d traversed 800 feet total in four minutes and 24 seconds.

And then two days later, on May 2, he dove past his previous mark and secured the 124-meter tag.

Today I decided to have another crack at shifting the Free Immersion record up a notch or two. I felt like if I avoided...

Posted by William Trubridge on Monday, May 2, 2016

Trubridge’s records are in the free immersion category, which is one of eight “disciplines” that free diving association AIDA International oversees. He also holds the world record in the constant weight no-fins category. Molchanova still holds both of those women’s records, as well as four others.

The dangers of free diving are plentiful – disorientation, blackouts, equipment failure – yet many insist that fatalities like Molchanova’s are rare, and that competition fatalities like Mevoli’s are even rarer. Statistics are criticized as unreliable due to under-reporting, but journalist and author James Nestor located the sport within “the outer limits of competitive risk.”

Trubridge has insisted in the past that it is a “safe sport.” He describes an other-worldly experience when he sinks to new depths.

“I have a relationship with the depths, they beckon me beyond my means, cold dark vacant pressure, forever night, endless dreams.”