Herbert Nitsch: The Deepest Freedive at 253 Meters and the Longest Ascent
Updated: 3 days ago
AIDA & Molchanovs Instructor Trainer
He is the founder of The Depth Collector and VD Freediving Taiwan. With over a decade of experience, he focuses on solving real-world freediving problems, from equalization to depth adaptation, using practical, field-tested methods.
No Limits freediving has fascinated me since I was ten, when my mum took me to see The Big Blue in a movie theater. The engineering behind those seemingly simple machines that carried legends like Mayol, Maiorca and Leferme into the deep blue still captivates me: all those ideas, inventions and adjustments that make a dive possible. I love that “I built mine in my garage” spirit. Today, at my own modest level, I love working on my sled, finding ways to inflate the lift bag faster at depth, and simplifying the system so fewer things could go wrong. Could this work better? Could I make that simpler? I love that process, especially the moment when a problem I have been turning over in my head finally has a solution.
I’m also in awe of the pioneers themselves. I mean, can you imagine starting a dive wondering whether your lungs could withstand the pressure, with doctors warning that going deeper could kill you? What goes through your head before you take that last breath? Curiosity, determination, sheer stubbornness, and the unshakable conviction that it can be done. I could spend hours reading about these people and trying to understand what drove them.
Herbert Nitsch is one of them, an inventor and explorer with dreams so big I can barely get my head, or my lungs, around them. His story makes me admire his imagination but also question some of his decisions, often in the same breath.
On the morning of 6 June 2012, Herbert Nitsch prepared to descend farther beneath the ocean than any human being had ever gone on a single breath.
The water off Santorini was rough. Nitsch was tired. He had not slept enough, and a recent training dive had left him with an ear problem. He would later admit that he needed more preparation and better conditions.
But the machinery of the project was already moving.
Years of work had brought him to this day. The sled had been designed, modified and tested. A support team had assembled. Cameras were waiting. Sponsors had invested. Nitsch himself had contributed nearly €100,000, according to the account he later gave L’Équipe. The entire project had reportedly cost around €250,000.
His target was 800 feet, approximately 244 meters. Beyond that lay the bigger dream: 1,000 feet, or 305 meters.
He believed the dive would work. He also believed that if it did not, the likely price would be damaged eardrums and a few painful days.
He clipped himself to the sled.
The machine carried him down through the blue and into the darkness below.
The officially recognized depth is 253 meters. At that depth, the surrounding pressure is more than 26 times the surface pressure. Nitsch reached his deepest point and began his ascent. The sled brought him within meters of air.
But Nitsch did not return intact.
The man known as the “Deepest Man on Earth,” nicknamed “the Robot,” spent months in hospitals and rehabilitation centers. For roughly six months, he used a wheelchair. He had to relearn how to walk, speak, write, and coordinate the right side of his body.
This is the story of the deepest freedive ever recorded. Yet the most extraordinary part began after he reached the surface.
His greatest ascent was still ahead. And this one would take years.
Herbert Nitsch: From Airline Pilot to Freediving World Records
Herbert Nitsch did not grow up beside a tropical sea or in an established freediving community. He was an Austrian airline pilot living in Vienna and a self-taught freediver.
He discovered freediving almost accidentally in the late 1990s, when his scuba equipment was lost in transit on the way to a diving holiday. Unable to scuba dive, he spent the vacation snorkeling instead. According to his official biography, after only ten days of freediving, he came within two meters of the Austrian national record.
Lost equipment had pushed him to improvise. That habit shaped his entire career: whenever he hit a limit, he looked for a way around it.
He brought a pilot’s mind to freediving. Aviation had taught him to understand systems, anticipate failures, and build in backups. His approach was far removed from the romance of Jacques Mayol and the dolphin returning home. Nitsch wanted to know how things worked, where they stopped working and what he could change. He broke the challenge of depth into physical and technical problems, then set about solving them one by one.
Between his flying schedule and life far from the ocean, he had limited time to train in deep water. So he found ways to make progress on dry land.
Away from competitions, he built strength and endurance while working on the flexibility of his lungs and diaphragm. Once he arrived at a competition site, he changed gears. He gave himself 7 to 14 days to adapt to the water and stopped strength and endurance training.
His routine then revolved around exhaled breath-holds on a couch, underwater play, static hangs at around 15 to 20 meters on exhalation, diaphragm stretching, and one deep training dive a day. Visualization was central to his preparation. He trained the dive in his mind as well as in the water.
The logic was clear: build fitness first, then give the body time to settle into the demands of depth.
Nitsch reports that his lung and diaphragm exercises increased his lung volume from seven to ten liters. With packing, he says, it rose to approximately fifteen liters.
His equipment followed the same spirit of experimentation.
In 2001, when dynamic freediving was still performed mainly with bifins, Nitsch saw the potential of the monofin already used in competitive finswimming. On 24 February, he swam 170 meters to set the first dynamic freediving world record achieved with a monofin. He also set the first constant-weight lake world record with one, helping bring the monofin into mainstream competitive freediving.
The night before that 170-meter swim, he had been busy solving another problem.
Drawing on his experience as a pilot, he thought about where ballast belonged. Weight should balance the body. If it pulled the legs down, the diver had to fight the resulting drag. His solution was wonderfully simple: a bicycle inner tube filled with lead pellets, wrapped around his neck and initially held in place with duct tape.
It was 23 February 2001. The modern freediving neck weight was taking shape.
Nitsch’s official biography credits him with 33 world records across nine disciplines, including the traditional Greek discipline of Skandalopetra. His range remains astonishing: 9 minutes 4 seconds in static apnea, 183 meters in dynamic, 134 meters in dynamic without fins, 83 meters in constant weight without fins, 120 meters in free immersion, 142 meters in variable weight and 124 meters in constant weight.
Those numbers matter. No Limit is sometimes dismissed as an engineering stunt, as though the diver simply holds on and enjoys the ride. Nitsch had already demonstrated exceptional breath-hold ability, swimming efficiency, depth adaptation and mental control across the sport. He brought all of that experience to the sled.
And the sled offered something muscle alone could not: a route into an entirely different part of the ocean.
What Is No Limit Freediving?
In Constant Weight, divers descend and return under their own power, carrying the same ballast throughout the dive. In No Limit, a weighted sled takes the diver down a line, and a buoyancy system brings them back.
The freedom to use mechanical assistance has taken freedivers to extraordinary depths. It has also turned the discipline into an arms race involving athletes, inventors, compressed-air cylinders, release mechanisms, lift bags, and increasingly complex safety procedures.
The descent is brutally fast. On Nitsch’s sled, he traveled feet first as the machine accelerated down the line. Every ten meters of seawater adds roughly another atmosphere of pressure. The lungs compress, equalization becomes harder, and nitrogen’s narcotic effects can grow stronger.
Traditional No Limit systems use compressed air to inflate a lift bag at depth. Its buoyancy then carries the diver and sled toward the surface.
Speed saves precious oxygen. It also means a huge pressure drop in very little time.
That is the problem at the heart of these dives. Moving fast shortens the breath-hold and limit the time spent under extreme pressure. But coming up too fast can increase the danger from nitrogen absorbed along the way.
Decompression illness can affect freedivers too. The air in their lungs contains nitrogen, and under pressure, some of it dissolves into the blood and tissues. As pressure falls during ascent, bubbles can form and contribute to decompression sickness.
A 2023 systematic review found evidence for both decompression sickness and arterial gas embolism as possible mechanisms of decompression illness in breath-hold divers. Different mechanisms, with potentially devastating consequences.
For most recreational freedivers, decompression illness is not the main danger. Beyond 200 meters, it demands serious attention.
Nitsch knew that. He had spent years developing equipment and procedures to reduce the risk.
The Freediving Sleds Behind Nitsch’s No Limit Records
Nitsch had his doubts about No Limit at first. Too much depended on the equipment, and the discipline already had a history of serious accidents and deaths.
Then he began breaking its records: 172 meters in 2005, 183 meters in 2006, and 185 meters in June 2007. The very next day, at Spetses in Greece, he reached 214 meters.
That dive became the last men’s No Limit world record listed in AIDA’s official history. Two months earlier, French record holder Loïc Leferme had died during training after a problem with his ascent system. The risks became impossible to ignore, and federations eventually stopped sanctioning No Limit records.
Nitsch continued independently.
For him, 214 meters still left room to explore. He was thinking in feet now: 800, then 900, then 1,000. Getting there would mean rethinking the machine that carried him.
Nitsch and his team built three increasingly sophisticated sleds.
The first, used for his 172- and 183-meter records, carried two inflatable lift bags supplied by scuba cylinders.
For the second sled, used at 185 and 214 meters, he replaced the inflatable bags with a rigid carbon dome filled with foam, positioned above his head. The dome acted as a permanent float: it provided the upward force needed for the return without requiring a bag to be inflated at the bottom. The redesigned sled was also faster in both directions, shortening the dive and reducing his time under extreme pressure.
For the 253-meter attempt, he went further. The new carbon-fiber sled was more streamlined, with a rigid dome providing the buoyancy for the ascent. Nearly two meters long, the yellow machine looked like a torpedo built around a man.
Ballast, guidance, buoyancy. And at the center of it all, a human being holding his breath.
An electric winch aboard the support vessel retrieved the dive line after the sled had ascended. It did not power his return. This arrangement was designed to avoid the tangling risks of a conventional counterweight system.
Nitsch considered it his fastest and safest sled yet.
EQUEX: How Nitsch Equalized on Extreme Freedives
Equalization required another invention. As the lungs compress during descent, moving air from them into the mouth becomes increasingly difficult. On a fast No Limit sled, there is little time to struggle.
Nitsch’s solution was the EQUEX, short for equalization extension tool.
At approximately 15 to 20 meters, he transferred most of his lung air into an external container, using reverse packing to extract more than he could through an ordinary exhalation. He then continued descending with what he described as “almost empty lungs,” using the stored air exclusively to equalize his ears and sinuses.
The system evolved with his records. First came a balloon inside a funnel. Then he used a dishwashing-liquid bottle during training, followed by a large plastic Coke bottle for his dives to 185 and 214 meters.
For the 253-meter attempt, he joined two Coke bottles back-to-back, with an opening at the bottom and a tube at the top. The bottles started the dive filled with water. As he transferred air into them, it pushed the water out through the lower opening.
As he descended farther, increasing pressure compressed the stored air, allowing water to enter again through the bottom. The air occupied progressively less space, but remained accessible through the tube at the top. He could draw it into his mouth for equalization without having to retrieve it from his increasingly compressed lungs.
That was the clever part. The EQUEX did not stop the air from compressing. It gave him access to it when his lungs could no longer supply it easily.
According to Nitsch, filling the EQUEX took approximately 23 seconds during his 185- and 214-meter dives. For the 253-meter attempt, the stop lasted about a minute.
A full minute on a single breath, before the deepest part of the dive had even begun.
The project was called Extreme 800.
Decompression in Freediving: Nitsch’s Ascent Strategy
Nitsch had also spent years working on how to come back safely.
Later in his competitive career, he deliberately slowed the final part of his ascent. During his No Limit records of 185 and 214 meters, he stopped at about 10 meters for a full minute, still holding his breath.
For Extreme 800, he planned to slow the sled between approximately 100 and 70 meters, then pause at around 10 meters for one minute before surfacing.
Later in his diving career, he had also introduced post-dive oxygen recompression, returning to a depth of 6 to 10 meters to breathe pure oxygen. At 10 meters, the surrounding pressure is roughly twice that at the surface. He aimed to use pressure and oxygen to help manage the nitrogen absorbed during the dive.
But no simple formula could make an exposure like this safe. Extreme breath-hold diving still left many questions unanswered.
Nitsch built pauses into a dive where every second cost oxygen, hoping a longer breath-hold would make the return safer.
Carrying out that plan depended on him staying conscious and in control.
Before the 2012 Record Attempt: The Warning Signs
Five days before the attempt, according to photographer Phil Simha, Nitsch had surfaced from a 200-meter training dive with an ear problem. The night before the record, Simha recalled taking the telephone away from him during an argument about contracts and sponsors.
Simha questioned whether the conditions were calm enough to proceed. Nitsch reportedly replied that he would not die.
His confidence rested on more than a decade of records. He had helped design the machine, trained his body for the depth and prepared emergency procedures. He trusted the backups. Before the attempt, he reportedly argued that serious freediving accidents came from avoidable mistakes and believed his methodical approach would keep him from making them.
Competence can reduce risk. It can also make you think you have accounted for everything.
Looking back, Nitsch was clear about his mistake. He still believed the dive plan was feasible, but he should have postponed, trained more, and waited for better weather. In his own assessment, 800 feet had been possible. Attempting it that day had been wrong.
None of the pressure behind that decision appears on a dive profile. The money already spent. The sponsors waiting. The cameras ready. Friends giving their time. Years of work aimed at one morning.
You can know that cancellation is an option and still find it desperately difficult to say the words.
By the morning of 6 June, Nitsch still had a decision to make, with all of that weighing on it.
He breathed, checked the system and began.
The 253-Meter Freedive: Beyond 800 Feet
The sled accelerated beneath Santorini.
At around 15 to 20 meters, Nitsch paused for about a minute to prepare the EQUEX.
At 100 meters, the pressure was roughly eleven times that at the surface. By 200 meters, the light had faded, and the pressure had nearly doubled again.
He descended feet first, using air from the EQUEX to equalize as the sled carried him past his previous record of 214 meters. Then past 800 feet.
He reached the deepest point of the dive, which Guinness recognized as 253 meters.
Now he had to come back.
The sled began its ascent, lifted by the buoyancy of the carbon dome above his head.
The deepest part was over.
The most dangerous part was beginning.
Nitsch’s Freediving Accident: Losing Consciousness on Ascent
At approximately 100 meters, he lost awareness.
Some accounts describe a blackout. Nitsch said he had fallen asleep, attributing it to nitrogen narcosis compounded by fatigue and the deep relaxation he used to conserve oxygen.
He could no longer slow the sled down.
It kept racing upward until its automatic system stopped it at approximately 10 meters, within reach of the safety divers.
The mechanical safeguard had worked. But the man it had delivered to them appeared unresponsive.
The safety team faced a brutal dilemma. They had a breath-hold diver who needed air, and a dive plan that called for him to remain underwater a little longer. Bringing him up meant abandoning the decompression stop. Keeping him there meant risking drowning.
They removed him from the sled and brought him toward the surface.
According to his own account, Nitsch regained consciousness while still underwater, at the surface h asked for oxygen, and returned to about 10 meters after surfacing, staying there for approximately 20 minutes. L’Équipe’s account, based partly on Simha’s recollection, describes him as confused and says the team put him back underwater with oxygen to limit the damage.
The accounts differ over how that decision unfolded but agree on the central sequence: the planned stop was missed, he surfaced, and he then returned to depth with oxygen.
Simha remembered Nitsch signaling that his lungs felt all right.
I watched the documentary Herbert Nitsch: Back from the Abyss. You can see him ask for a mask, go back down to breathe oxygen, then point at his head. That gesture stayed with me.
I cannot begin to imagine what he felt down there. Ten meters below the surface, breathing pure oxygen, aware that something was wrong inside his head, with no way of knowing how bad it was or what would happen next.
Gosh, it gives me chills.
The effects of severe decompression illness were becoming apparent. He was taken ashore by Zodiac, transferred to emergency medical transport, and flown to Athens for treatment in a hyperbaric chamber.
Recovery After the Dive: Learning to Walk and Speak Again
Nitsch described the decompression illness as equivalent, in his case, to several strokes. Later accounts reported severe neurological damage affecting movement, coordination, memory, and speech.
He spent more than a week receiving treatment in Athens, then traveled by medical aircraft to Murnau in southern Germany for about a month of recompression treatment. Further rehabilitation followed in Vienna.
The athlete who had controlled his body across every freediving discipline could no longer rely on it.
For approximately six months, he used a wheelchair. His right side responded slowly. His speech, balance, and memory were impaired. Writing his own name became difficult.
During a public appearance months later, admirers offered notebooks for autographs, but his right hand could not produce the signature that had once accompanied dozens of world records.
The psychological toll was equally severe. Nitsch understood enough to recognize what he had lost. During rehabilitation in Germany, he contemplated suicide. He would later speak about that period with bleak humor, but the despair beneath it was real.
He promised his father that he would not die.
That promise carried particular weight. L’Équipe reported that Nitsch’s brother had died after a road accident two years earlier. His father, Gerhard, had already lost one son. Now he was helping the other find his way back.
Recovery was slow, repetitive and often frustrating. Progress was measured in steps, words, coordinated movements and marks made by a reluctant hand.
Nitsch resisted pessimistic predictions. He changed his diet, exercised and brought his familiar determination to rehabilitation.
He kept working, unwilling to accept that his condition would always remain the same.
The stubbornness that had carried him into danger was now part of his daily effort to recover.
Returning to Freediving: Ten Meters in the Cook Islands
At the beginning of 2013, Nitsch’s father took him on a cruise through the South Pacific. The journey brought him back into contact with people, sunlight, and the ocean. He lectured aboard the ship even though speaking remained difficult.
Then he returned to the water.
It was raining in the Cook Islands. The reef was damaged, and the setting was not especially beautiful. Nitsch descended to approximately ten meters.
He was happy to be underwater. He was also confronted by how much had changed.
He kept diving. In French Polynesia, he swam, fished, and encountered manta rays. Later, he returned to the sea in Palau and Rhodes. Underwater, movement could feel easier than it did on land.
His official biography describes him as fit and diving deep again within two years of the accident.
He did not return to elite competition. But he returned to the ocean and kept diving.
Record Depth and Rescue Accounts: A Note on Accuracy
Guinness World Records recognizes the Santorini dive of 6 June 2012 at 253 meters. Nitsch’s website gives 253.2 meters, while his first-person statement published on 6 June 2013 gives 249.5 meters. The sources used here do not explain the difference.
Accounts also differ over parts of the rescue sequence, particularly the decision to return underwater with oxygen. Those differences are retained where they matter.
The equipment and training descriptions draw primarily on Nitsch’s own website and biography. His lung-volume figures are presented as his reported measurements. His general use of post-dive oxygen recompression is distinguished from the specific ascent plan described in his account of Extreme 800.
Nitsch described severe decompression sickness with neurological consequences equivalent to several strokes. This article draws on his public account and published reporting, rather than a complete medical case record. He attributes his loss of awareness during ascent to decompression sickness
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Sources on Herbert Nitsch and No Limit Freediving
L’Équipe Explore, “No Limit: À bout de souffle”, based on interviews with Herbert Nitsch, Phil Simha and other figures in deep freediving.
Guinness World Records, “Deepest No-Limit Freedive (Male)”, Santorini, Greece, 6 June 2012.
Herbert Nitsch, “World Records”, official website.
Herbert Nitsch, “Pioneer”, official descriptions of his equipment, training, lung-volume work and decompression procedures.
S. Lesley Blogg, Frauke Tillmans and Peter Lindholm, “The Risk of Decompression Illness in Breath-Hold Divers: A Systematic Review”, Diving and Hyperbaric Medicine 53, no. 1 (2023): 31–41.
“Herbert Nitsch Talks About His Fateful Dive and Recovery”, Nitsch’s first-person statement reproduced by DeeperBlue.com, 6 June 2013.
Herbert Nitsch, official English biography, 2024.
Herbert Nitsch: Back from the Abyss, documentary, viewed by the author.
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