The breathtaking world of freediving

Hanli Prinsloo has invited me for a swim with the seals of Duiker Island, just outside Hout Bay. April is apparently a good month for cute seal pups. A hot berg wind is blowing and Prinsloo soaps up to ease herself into a snug wet suit.

She is smaller than I expected and, at first glance, does not resemble an extreme athlete who can hold her breath for up to six minutes in a swimming pool, or reach depths of 64m without supplementary air.

“I like to use jasmine body wash,” she says, as suds course down her arms. “When I smell jasmine I feel happy, because I know I am going to dive.”

Although humans have been diving without supplementary oxygen for millennia in search of pearls, sponges and other sea treasures, competitive freediving – the aim of which is to dive as deeply as possible on a single breath of air – is a relatively new extreme sport. It has a reputation for being extremely dangerous; only base jumping – in which participants jump from bridges and buildings with parachutes – is considered more risky and has been banned in several countries.

But despite the potential danger, freedive schools have started popping up everywhere from California to Thailand. The sport has received considerable media attention and there have been recent articles in The New York Times, Atlantic Monthly, Smithsonian and Outside magazines. The film The Big Blue, a fictionalised account of the rivalry between a pair of actual divers, has become a minor cult classic.

Boundaries of human physiology
Freediving is at once mystical, beautiful and deeply unsettling. The world’s first freediving championships, organised by the International Association for the Development of Apnoea, were held in 1996. Since then records have been broken yearly, sometimes even monthly, as athletes explore the boundaries of human physiology.

Divers compete in three categories: constant weight with fins, constant weight without fins and free immersion, in which contestants pull themselves up and down on a rope. In the no-limits class, considered too technical for competitions, divers descend on a weighted sled and are drawn to the surface by air balloons.

Until the 1960s it was believed that diving beyond 38m would result in fatal pulmonary pressure damage. This has been proved wrong. Herbert Nitsch, an Austrian diver, holds the world record in the no-limits category after he reached a depth of 214m in 2007 and surfaced unharmed. Later this month he plans to dive to 244m.

William Truebridge, a New Zealander, holds the free immersion and fin world records of 116m each. In Dahab, Egypt, Sara Campbell, an English woman, dived to 105m wearing a mono fin.

Scientists now understand that these feats are possible because of the mammalian dive reflex, an evolutionary adaptation strongest in seals and whales but present in all mammals.
“Immersing your face in cold water drops the heart rate sometimes as low as the 20s, thus reducing oxygen consumption,” says Prinsloo. Vasoconstriction in the arms and legs then directs oxygenated blood away from muscles towards essential organs such as the heart and brain.

Mental strength
Divers usually swim in a meditative trance with their eyes closed, keeping movements to a minimum – both thinking and moving consume oxygen. Mental strength is as important as physical ability and training includes meditation, stretching and yoga. After a period of breath-holding the diaphragm begins an uncomfortable series of involuntary contractions, or convulsions.

“Your body is telling you it is time to breathe, but you still have plenty of time because the spleen will contract, releasing a store of oxygenated blood into the system,” says Prinsloo. After 30m, a diver stops swimming as his or her compressed body achieves negative buoyancy and, assuming a head-down skydiver’s pose, he or she actually falls into the depths. “The ocean opens up and I surrender to it.”

As the pressure increases and lungs are squeezed to the size of fists, the mammalian dive reflex causes the vessels in their walls to swell, protecting the organs from collapse and damage. Pressures are so high that, if a diver was to open his or her mouth, water would flood the lungs, causing instant death. But humans, no matter how well trained, cannot hold their breath forever and if oxygen levels drop too low the brain shuts down, resulting in a blackout. The larynx closes in spasm, sealing the airways to prevent water entering. In this most extreme form of the dive reflex, people have been known to survive for up to 10 minutes.

Blackouts, however, are not acceptable in competition diving and, as a safety measure, contestants are required to pass a series of actions after surfacing. They must immediately remove their goggles, give a hand signal to the judges and say “I am okay”. Failure to complete the protocol results in disqualification. Points are not deducted for nosebleeds, caused by pressure-traumatised blood vessels, but it is not uncommon for competitors to emerge too cramped, hypoxic and incoherent to pass the surface protocol.

One function of the safety crew – on hand at all competitions – is to encourage blue-faced, unresponsive divers to breathe. Although there has yet to be a documented case of drowning during a competition, British diver David King, at the world freediving competition held last year in Greece, suffered an underwater blackout and needed chest compression, oxygen and a brief stay in hospital for a torn blood vessel in his larynx.

Competitive freediving
Freediving is not a spectator sport; the action takes place deep below the ocean. A diver rests motionless before descending, legs supported by a pool noodle. The judge counts down, the diver gulps air, then dives and disappears. Minutes later a head breaks the surface. The diver is either okay or not. If he or she blacks out underwater, he or she is hauled up by a lanyard attached to the ankle.

Competitive freediving is no way to make a living. Sponsors are rare, entering competitions can be expensive and winners take home nothing more than a medal. So why would anybody choose the sport?

Prinsloo tried scuba diving at the age of 18 and found it restrictive and frustrating. A year later, when she was studying in Sweden, a friend invited her freediving. The water of the fjord was murky, rough and freezing cold. Her borrowed wet suit leaked.

“I got to the bottom and sat on the sand,” Prinsloo says. “There was nothing to see and I thought: ‘This silence, this is exactly where I want to be.’ It is like an addiction.”
Divers describe feelings of intense peace, or an incomparable sensation of calmness. For many, diving is an extreme form of meditation and the ocean an enormous isolation tank. Even the discomfort is viewed positively.

Prinsloo says the high water pressure is a sort of reassuring oceanic embrace, something wonderful that awakens the dive reflex. It is said that if scuba divers and snorkellers dive into the sea, freedivers dive into themselves.

I Am Water
But the South African freediving community is small – just two or three men and Prinsloo – and there are no local competitions. Last year Prinsloo’s training towards the no-fins world record of 62m was interrupted by a laryngeal injury. She reached 56m and was stopped when she had trouble equalising the pressure in her ears. She plans to attempt the record again.

When not training or competing, Prinsloo swims with manta rays, whales and sharks in an effort to raise awareness of ocean conservation through her “I Am Water” trust. She earns a living giving motivational talks, teaching yoga and running training courses on the techniques of breath-holding. Thanks to her work with South African big-wave surfers and the subsequent media exposure, surfers from around the world are seeking her out.

“I am often asked how I can change someone’s physiology in one day. I do not. I help them to understand their physiology,” says Prinsloo. “Our bodies are much more comfortable in the water than most people know.”

“It is not as if Hanli taught me to charge harder, or take bigger drops,” says Mike Schlebach, a regular surfer at the big-wave break of Dungeons in Hout Bay. “She just made me aware of what my body is capable of. Before the training some guys thought that when they were held down and had convulsions they were going to die. Hanli’s training reinforces that when faced with [a wall of] white water, it is best not to think. Stay calm and take your breaths, then keep your mouth closed.”

“It is the panic that kills you,” Prinsloo says. “I teach people to remove themselves from the panic and that buys extra time underwater.”

On the boat from Hout Bay, we find the seals hot and sleepy, drowsing in the water with a forest of flippers held aloft in an effort to cool off. They appear thrilled to see us. They begin bulleting about, leaving streams of bubbles in their wakes like vapour trails and staring up at us as they pass.

Prinsloo pulls on a pair of long, custom-made carbon-fibre fins and slips into the water. Submerged she is transformed, her movements languid and serpentine. She looks perfectly at home.

Martinique Stilwell
Martinique Stilwell works from Cape Town, South Africa. Writer, doctor, surfer, sailor. Thinking Up A Hurricane. Martinique Stilwell has over 238 followers on Twitter.

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