The Science of Sport 1: Pressure Cooker

A collection of essays from Coast Mountain Culture’s writers that explores how science supports our bodies as we play in the outdoors.

Your baby did it. Blue whales, too. How Kimi Werner — culinary crusader, world-calibre spearfisher and ace freediver — mastered the freakish art of apnea, and in doing so lives a tasty and tasteful life far beneath the sea.


Gentle Giants? An average of four shark bites per year happen in Hawaii. Fatal attacks are extremely rare. Werner errs on the side of the odds.

holdingitdownOur ancestral ocean hunters freedived to retrieve sponge and pearls, and to recover sunken treasures. Now, many hundreds of years later, competitive apnea has become a controversial niche sport. The pressure, figurative and literal, on the body and mind in deep water is enormous. Freedivers manipulate the mammalian diving reflex that all humans share with whales and seals, which puts their bodies into oxygen-saving mode, allowing them to dive deep on a single breath. Upon initiating the reflex, three things happen: your heart rate slows, you shut down blood flow to extremities, and finally a “blood shift” occurs, where blood vessels constricting in limbs force blood into the body’s organs and simultaneously fill lungs with plasma, preventing them from collapsing at depth. This all happens by 98 feet below sea level: the world record free dive is 702 feet.

Provided things are still going well at this depth, you must also be wary of the building carbon dioxide in your bloodstream, which feels a lot like being shit-faced drunk and, much like on land, can result in making critical mistakes that could lead to blackout or death. Throughout all of this you must both ignore but simultaneously listen to your brain that, through reflexive contractions, is instructing your body to breathe. “It’s like a hiccup that goes through your body from your diaphragm,” explains Werner. “A lot of people, the minute they feel it, think they need to get back to the air. But you can stay down longer. Through experience you learn you might be able to have many contractions before you’re actually out of breath.”

Though Werner took the title of 2008 US National Spearfishing Champion in her rookie year and has impressive personal bests that include a dive depth of 159 feet and breath hold of four minutes 45 seconds, she says she “didn’t really even push it for those. I hunt for food, not for records, so I’m really conservative.”

An average deep dive for Werner is 80 feet, but she’s never under for longer than two minutes. “That’s when I want to surface because that leaves plenty of room for error,” she explains. Currents can get stronger requiring her to swim harder against it; a shark could scare the crap out of her — although given the great white scenario, that seems unlikely — or she could snare a fish that puts up a particularly good fight. All of these things cost oxygen. Relaxation, however, will preserve it, so that is the first priority.

The heart slows on exhales, so she makes them twice as long as her inhales. She pulls her breath from her diaphragm, not her upper lungs. “That’s how babies do it — another one of those things that for whatever reason our brains have taught our bodies to do it a different way that’s not helpful for diving,” she says. Werner also has a natural ability to equalize — to release the pressure in her ear tubes, as she gets deeper beneath the surface — without pinching her nose. It’s a skill that few freedivers share, and it means she remains hands-free, therefore even more relaxed when underwater.

For competitive freedivers, it’s all about going deeper; it’s about thrill. For Werner, it’s about gauging how the sun refracts through the water and changes her sight lines, and about reading a fish’s next move. It’s about catching her food. She lives almost entirely off the sea, trading her catch for the fruits and vegetables that her neighbours grow or slicing her fish into barbeque-perfect fillets and exquisite sushi feasts to eat on the beach before a Maui sunset.

It’s an enviable-sounding existence, and since Werner claims everyone has the power to control the mammalian diving reflex, perhaps we could all live this dream life, too? On second thought, we probably shouldn’t hold our breath. Kate MacLennan is a writer, editor and displaced surfer currently living in North Vancouver, BC. She is the managing editor of Lululemon Athletica’s global blog.

Author / Contributor

Kate is a writer, editor and content strategist—print, digital, social, etc. She likes to keep busy. Right now she’s holding down a gig at lululemon as its Blog Publisher (tune in for fresh things about to happen there), and is Vancouver Editor of 

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