The Man Who Plunged to Record Ocean Depths

On June 6, 2012, freediver Herbert Nitsch slipped into the azure waters off the coast of Santorini, Greece, attempting to break his own world record for the deepest a human could travel underwater on a single breath.  

The sport is called “No Limit” freediving. There are 10 sanctioned disciplines of freediving including “Dynamic With Fins” (how far you can swim in a pool while holding your breath) and “Constant Weight” (swimming as deep as you can and returning to the surface while carrying a weight), but No Limit is the most extreme.  

In No Limit, the freediver rides a weighted sled that descends on a rope hundreds of feet below, exposing the body to crushing pressure and extreme cold. Minutes later, the sled buoys the diver safely back to the surface, if everything goes right.    

Because of the extreme physiological toll of deepwater diving, it’s common for freedivers to black out during or after a dive. Competition rules state that participants must remain conscious for a certain amount of time to qualify for a record.  

It’s also tragically common for freedivers to die doing the sport they love. Audrey Mestre, Natalia Molchanova and Loïc Leferme are just some of the freediving greats who lost their lives in the water.  

In 2007, Nitsch descended to 702 feet on his custom-designed sled, setting a new world record and earning him the title (from Playboy magazine) of the “deepest man on Earth.” But Nitsch had greater ambitions—he wanted to break the 1,000-foot barrier. To get there, he planned to stage increasingly deep dives past 800 feet, 900 feet and finally 1,000.  

In Santorini in 2012, Nitsch successfully descended to 830 feet—a new world record that still stands today—but he nearly lost everything in the process.  

Herbert Nitsch stumbled into freediving by accident. He was a professional pilot for decades and loved to travel. On a scuba diving trip to Egypt, his equipment was lost in transit, so he decided to spend the week snorkeling.  

Nitsch borrowed an underwater camera and spent hours taking photos of the stunning sea life. Distracted by the scenery, Nitsch would stay submerged for minutes at a time. When he surfaced from one of his dives, a scuba diver friend asked Nitsch how long he’d been freediving. Nitsch had never heard of freediving—he was just “snorkeling.”  

Nitsch borrowed his friend’s diving gauge and decided to see how deep he could go on one breath. On his first attempt, Nitsch descended 32 meters (105 feet). Not bad, he thought.  

“A few weeks later, this same guy called me and said, ‘Do you know the Austrian freediving record is 34 meters, only 2 meters deeper?’” says Nitsch, who is Austrian. “He said, ‘Buy yourself some decent fins and set a new record.’ And more or less, that's what I did.” 

Nitsch was officially hooked on freediving. His pilot job didn’t give him much free time to train, but Nitsch was amazed at how much longer he could hold his breath just by calming his mind and letting his body access the stores of oxygen naturally present in the lungs and bloodstream.  

“The dive reflex happens automatically—you just have to allow it to happen,” says Nitsch, who also set a freediving world record in the “Static Apnea” discipline, in which divers hold their breath for as long as possible in a pool. Nitsch’s record was 9 minutes, 4 seconds. “You learn that it would be good to breathe again, but you don’t have to.” 

While freediving has been practiced for centuries by traditional sponge divers and spearfishers who made their livelihoods by holding their breath underwater, it’s relatively new as a competitive sport. The main governing body of freediving, the International Association for the Development of Apnea (AIDA), was founded in 1992.  

Since freediving is such a new discipline, competitors develop their own techniques and training methods. As a pilot, Nitsch says he couldn’t train as much as the competition, but he could “train smarter.” For example, instead of making a series of increasingly deep training dives to improve his lung capacity, he would dive 60 feet and perform “static hangs” on fully exhaled lungs, allowing them to deflate fully to mimic the high-pressure conditions that cause blood to shift from the extremities to the core and brain.  

At home between flights, Nitsch even performed what he called “couch training,” doing a series of deep and long exhales and breath-holds on the couch while watching American sitcoms.  

When an Army friend let Nitsch borrow his monofin—a single fin that connects both feet and allows a diver to swim like a dolphin—he decided to try it in competition for freediving disciplines like Constant Weight.  

"At first, people were laughing their heads off, because here comes the Austrian who thinks he knows better,” says Nitsch. “But after shattering their records, they thought maybe there’s something to it.” Now there are separate freediving categories for monofins, bifins and no fins.  

With his unconventional training methods and equipment hacks, Nitsch set record after record across multiple freediving disciplines, but there was one competition that spooked him—No Limit.  

“First of all, I thought I couldn't go that deep, and second of all, it's very technical and dangerous,” says Nitsch. (No Limit has claimed so many lives that AIDA stopped sanctioning the sport.) When Nitsch finally felt ready to attempt No Limit, he was determined to do it his way—applying the same out-of-the-box thinking and determination to push the limits of human endurance.  

The most popular freediving discipline is Constant Weight, in which divers descend and ascend on their own power using a monofin, bifins or no fins at all. Alexey Molchanov, the star Russian freediver, holds the world records in both Constant Weight (446 feet) and Constant Weight with Bifins (417 feet). Petar Klovar, from Croatia, holds the record for the deepest Constant Weight dive without fins (338 feet).

The biggest difference between No Limit and most other freediving disciplines is the use of a “sled.” Instead of descending on their own power, No Limit freedivers ride a weighted sled feet-first down a long rope. Once the freediver reaches their target depth, they inflate an airbag on the sled using a scuba tank. The “buoyancy device” then lifts the diver back up the rope to the surface at speeds exceeding 10 feet per second.  

The speed of both the descent and the ascent is key to making a successful deep No Limit dive. The longer a freediver is below 300 feet, the more nitrogen and other gases are absorbed by the bloodstream and body tissues. When a diver passes 600 feet, the pressure is so great that the lungs are squeezed to the size of lemons. No Limit freedivers try to limit their exposure to those extreme conditions by descending and ascending as quickly as possible. But not too quickly.

The greatest threat to a No Limit freediver is decompression sickness, also known as “the bends.” When a freediver ascends toward the surface, the water pressure lowers dramatically. If the pressure falls too quickly, it causes the nitrogen absorbed by the body to come out of solution, forming tiny bubbles that can travel to the brain and trigger life-threatening strokes.  

"It's like opening a bottle of champagne too quickly; the bubbles spread everywhere,” says Nitsch. “That’s more or less what happens inside the body. To prevent that from happening, you need to open the champagne bottle slowly. In freediving, that means slowing your ascent or making a safety stop to release the nitrogen safely.” 

To chase the world record, Nitsch designed his own No Limit sleds to maximize his speed on both descent and ascent. But one of the remaining challenges of descending so quickly was equalizing sinus and inner ear pressure while descending so fast. To overcome this, Nitsch devised a simple trick using an empty plastic soda bottle with holes at its bottom and a straw-like tube on the top. At the start of his descent, the bottle is filled with water, and Nitsch exhales air from his lungs into the soda bottle. Then, as he goes deeper, Nitsch inhales small sips of air from the bottle and uses them to equalize the pressure in his sinuses and ears.  

From 2005 to 2007, Nitsch improved his sled design and soda bottle technique to push progressively deeper, setting and breaking his own No Limit world record again and again. Then, on April 11, 2007, the French freediver Loïc Leferme died while training to break Nitsch’s world record, but that didn’t stop Nitsch from continuing to push the envelope. Two months later, Nitsch rode his sled to a depth of 702 feet, the last No Limit world record sanctioned by AIDA. It was the dive that earned him the title of “the deepest man on Earth.”  

But Nitsch wasn’t done.  

Five years after his record No Limit dive of 702 feet, Nitsch was ready to push the sport of freediving to new extremes. His goal was 1,000 feet—unimaginable even a few years earlier, but something that Nitsch believed was achievable with the right equipment, the right team and the right mindset.  

His first step was to make a No Limit dive beyond 800 feet, which required a completely redesigned sled. Gone were the inflatable lift bags, which Nitsch felt were unreliable. In their place, he installed a solid carbon dome and two scuba tanks that released jets of compressed air that rocketed the sled to the surface. To avoid decompression sickness, Nitsch planned a long decompression stop at 60 feet below the surface to slowly release the nitrogen from his blood.  

Nitsch and his safety team trained and prepared for years for all possible contingencies. On June 6, 2012, Nitsch donned his wetsuit and fluid goggles and rode his space-age sled to a record-breaking depth of 830 feet. Nitsch activated the compressed air, which sent him and his sled racing toward the surface in a stream of air bubbles.  

Everything went according to plan on that record-setting day in 2012 until Nitsch reached his 60-foot decompression stop. To his team of safety divers, it looked like Nitsch had blacked out. Nitsch floated limply away from his sled and his crew panicked. If they didn’t get Nitsch to the surface quickly, he was going to drown.  

The reality, however, was even stranger: Nitsch had fallen asleep. Freedivers who travel to extreme depths experience “nitrogen narcosis,” an overload of nitrogen in the bloodstream that makes them feel drunk.  

“The deeper you go, the stronger the narcosis is," says Nitsch, who was not only “drunk” on nitrogen, but in a deep meditative state to lower his heart rate and limit oxygen consumption. “So this combination of being drunk, relaxed and really tired caused me to fall asleep.”  

Believing that Nitsch’s life was at risk, his safety team started bringing him to the surface. Nitsch woke up and immediately realized the danger he was in by failing to properly decompress. He tried to stop ascending, but because his goggles had slid off his nose, he could not locate the dive rope properly. Once at the surface, he grabbed an oxygen tank and swam back down to 60 feet in hopes of somehow staving off decompression sickness, but within minutes Nitsch started to feel the effects—numbness, pins and needles, confusion. It was too late.  

The nitrogen bubbles traveled to Nitsch's brain, causing a series of small strokes that rendered him unresponsive. Nitsch was flown to an Athens hospital with a hyperbaric chamber, where he spent the next week in a coma as doctors desperately tried to reverse the crippling effects of nitrogen poisoning.  

When Nitsch woke up at a trauma hospital in Germany, he was unable to walk and barely able to speak. His doctors initially thought that he’d spend the rest of his life in a wheelchair and suffer permanent cognitive impairment from the strokes. Against the advice of doctors and his family, Nitsch left the hospital and quit taking medication. Nitsch battled for many months to regain his short-term memory and recover the ability to walk unassisted and speak fluently. 

After two years, Nitsch was able to get back into the water. Not as a competitive freediver, but simply to enjoy the unmediated connection between humans and the underwater world that freediving offers. “Maybe I dive a little deeper than other people, but it’s just for fun,” says Nitsch.   

Nitsch’s 830-foot No Limit dive remains the deepest dive ever. Since AIDA stopped sanctioning No Limit dives, Nitsch’s near-death achievement was confirmed by Guinness World Records. In his freediving career, Nitsch set a total of 33 world records across nine disciplines.