Leonie Sherman
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Exploring the depths of human endurance on one breath

The Bajau, a semi-nomadic people spread throughout Indonesia, Malaysia and the Philippines, grow up underwater – some of them spend 60% of their lives there.  BBC footage shows them walking on the sea floor 65 feet below the surface searching for shellfish like they’re roaming the aisles of a grocery store. They’ve evolved larger spleens than neighboring groups, which allows them to dive deeper and hold their breath longer. They are the world’s best freedivers.

Even though humans have been plunging underwater for millennia, modern freediving began in 1949 when an Italian man dove almost 100 feet below the Gulf of Naples on a dare. People immediately wanted to break his record. Fifty years later, there are six officially recognized freediving competitive disciplines. The world record for static breath hold stands at almost 12 minutes, and the deepest anyone has reached under their own power is 413 feet.

instructor and student diving side by side during a course

Instructor and student diving side by side during a course (Photo: Michael Timm)

But about 90% of freedivers are purely recreational. For about $500 – the cost of a neoprene exposure suit, mask, fins, goggles and a weight belt – anyone can join.

The art of exploring the ocean depths on a single lung full of air is the fastest growing water sport in the world. And the waters off the coast of California provide the perfect training ground for developing skills that can be enjoyed all over the world.

“If you train out here in California, with limited visibility, a surf entrance, unpredictable swells and frigid water, it makes you more confident so you can handle environmental variables anywhere else in the world,” explains San Diego-based instructor Michael Timm, who has been teaching freediving for 14 years.  “If you can dive 90 feet in California, you can dive 120 feet anywhere else.“

Training in California doesn’t make a diver invincible, as the surfing community learned in 2001 when Jay Moriarity died freediving solo in the calm warm waters of the Maldives. “There is no warning for when you get into trouble, so this is a very rule heavy sport,” explains Timm. “If you don’t follow the rules you are going to die.”

The first rule is to dive with a buddy, who will notice signs like a nodding head, tremors, blue lips, dizziness or confusion that can lead to a blackout. The second rule is to get your weight belt dialed in appropriately. The correct weight makes a diver positively buoyant on the surface after an exhalation. Too much weight means a quick descent, but slows the ascent and will send a diver to their death below the surface if they experience a shallow water blackout. Other rules include not hyperventilating, taking three recovery breaths at the surface, and not exhaling until you reach the surface, to maintain buoyancy.

dynamic swim with bi-fins practice

Dynamic swim with bi-fins practice (Photo: Michael Timm)

Like most adventure sports that can kill you, ego and peer pressure are the main causes of freediving casualties. Unlike other adventure sports that can kill you, freediving requires relaxation. Before the peak inhalation that carries them to depth or distance, a diver needs to breathe and relax for a full minute or two. “The final breath should be slow and deliberate. You need to think happy positive thoughts,” explains Timm. “So drop any expectations, forget about time and depth and sink into the feelings, focus on relaxation and equalization.“

Of course, it’s hard to relax when you can’t breathe. The first night of a PADI introductory freediving course takes place in a classroom to learn the theory of why you can hold your breath longer than you thought. It comes down to the delicate balance between CO2 and O2.

“Carbon dioxide is the alarm system in the body, it tells a person when they need to breathe,” explains Timm. “When a person holds their breath, oxygen levels drop slowly, but CO2 levels rise quickly. In effect, the body is giving the alarm too early, telling you to breathe before oxygen runs out.”

student practicing “free immersion” diving

Student practicing “Free Immersion” diving (Photo: Michael Timm)

It’s also hard to relax when you feel like your skull is a thin-shelled egg being crushed by a giant’s hand, which is what diving at depth feels like. On the second day of an introductory freediving course, students learn to equalize early and often, to bring the pressure inside their ears, mask and sinuses to the same level as the water around them.

While scuba diving, with a constant supply of air, a diver can simply hold their nose, exhale forcefully and pop their ears. But freediving requires a more complex and subtle approach, to conserve energy and preserve relaxation. Trouble equalizing is the major limiting factor in freediving and the reason 20% of participants fail their first course.

relaxed ascend from depth at the line

Relaxed ascend from depth at the line (Photo: Michael Timm)

After an evening in the classroom, the first full day of a PADI introductory freediving course takes place in a pool, where students can put theory into practice, and push through their fears in a safe controlled environment. They graduate to open ocean diving only after practicing breath hold, and mastering descent, ascent and rescue in a pool.

students practicing the rescue of a simulated blackout diver

Students practicing the rescue of a simulated blackout diver (Photo: Michael Timm)

Breath hold practice is controversial in American pools. “I train military divers, many under the age of 21, who here in the US are allowed to carry and use an MK 15, but not allowed to legally buy a bottle of beer – even these elite soldiers aren’t allowed to practice  breath holds on their own time in a  pool,” explains Timm, who originally hails from Germany. “In Europe you can lay on the floor of a pool for three minutes and nobody cares, but in the US if you swim a 25-meter lap while holding your breath, they yell at you and pull you out of the pool. The only reason we can do it at the pool in San Diego is because it’s off hours and there’s no lifeguard on duty.”

Despite growing regulatory hassles and inherent dangers, Timm is committed to training new freedivers, work which takes him from the frigid waters of Alaska to the clear desert lakes of Nevada and the warm oceans of the tropics. “We are teaching people to be safe in this sport,” he says. “Our goal is to prevent people from going out by themselves and drowning. We are educating people to do this safely.”

But like all passionate athletes, Timm is ultimately driven by love for the sport. “I feel like I’m meditating when I’m down there. I don’t think about anything, I’m just gliding through the water, everything but the present moment drops away.”


Dive California offers tours and classes and is based in San Diego. If you want to find an outfitter closer to home, make sure they are certified by a recognized agency, such as AIDA, PADI, or SSI.


Main photo: Freediver ascending on the line (photo by Michael Timm)

Read other articles by Leonie Sherman here.