We all freedive for a reason. Maybe it's because we want to challenge ourselves, test our limits, or maybe just to go someplace quiet, far away from the noise of the city. In this awesome TEDx talk, William Trubridge answers the most important question of all, "why do you do it"?

Do you remember what it was like to hold your breath underwater, in complete darkness, and for what seemed like forever? Who remembers that? You see, you've all done it, everyone. It was your first breath hold and had no real beginning, and it ended with your birth and your first breath. We forget that, don't we? We forget that we came into this world holding our breath.

So how would you like to go back to that quiet, liquid, weightless world? Shall we go? Should we take a free dive together? Okay. Relax and picture yourself lying on the surface of the ocean and gazing down into the blue, watching those flickering beams of sunlight converging on a point far, far below you. Where you're going is far beyond even that, to where those beams have diffused into, at best, a kind of pale, pale light. You suck in a last critical breath of air. It's a breath that's going to have to be your life support system for the next several minutes.

Your body jackknifes upside down, your arms sweep the water and pull you under, and straight away, you feel the pull of your own buoyancy tugging you back to the surface,
holding you back, asking you, "do you really want to go"? If you do, you need to swim as quickly and powerfully to overcome that force, but be careful: don't use too much energy, because this is the phase of the dive where you burn the most oxygen. Your legs kick, your arms sweep the water, and the cycle repeats. Gradually, the surface lets you go.

Inside your body, your lungs are compressing due to the pressures of water column above you, and by 10 meters, they're already half the volume that they were on the surface, meaning that the average density of your body has increased. When that density matches exactly the density of the water outside your body, then you're neutrally buoyant - if you stop here, you would float, suspended and immobile.

So when you continue on beyond this point, it's like you have to leave a part of yourself behind; you leave behind your history, your hopes, your regrets, your worries. From this moment on, there is only your present self in the present moment. You've even left behind the concept and the memory of breathing itself, of being terrestrial, and you continue with this conviction that you are aquatic - you're like a rocket that sheds its payload and continues on only with what is necessary for the journey.

You see, the less of yourself you take down, the lighter the load. Two more longer, slower, easier strokes, and you're coasting downhill now. You can shut off the engines. From this point on, you're negatively buoyant, so your arms fall to your sides, kind of tucking in there like a gannett as it plunges towards the water. Every muscle in your body relaxes, except for maybe your feet, which act like tiny little rudders to keep you on a vertical track. What you're doing free-falling - I mean, the reality is that it would kill you if you only do it long enough, but at the same time, it's the most beautiful part of the dive, where you feel like you're being accepted and absorbed into the ocean. Even your eyelids droop and cover your eyes. Every second or two, they may blink open to check your position next to the rope; every second or two, your tongue pumps a little bit of air up into your middle ears to equalize the pressure there. Your lungs are compressing further still, losing more volume and creating a kind of a vacuum effect that's collapsing your ribcage, collapsing your bronchi and your trachea, and pulling your diaphragm up underneath your ribcage.

So there's nothing about what's happening in your body that resembles any other sport or activity. But why would it? What you're doing is perhaps the most alien thing a human body can do. Sure, if you take a spacewalk, then you're off the planet and you're weightless, but a free dive transforms you into another creature altogether.

It's dark now. It's a kind of penumbral twilight. It doesn't really matter; there's not much to see down here anyway. There's very little to hear, either. Someone could be letting off fireworks on the surface, and you wouldn't hear it. At best, all there is is the kind of dull thudding of your heartbeat, which has slowed to less than half its resting rate; it's so slow that there's this kind of eerie pause between the two phases of the beat, so instead of being boom-boom, boom-boom, boom-boom, it's more of a glung … Of course, you're on your way towards a certain depth; there's a target, a white disc at that depth that holds the tags you have to retrieve and bring back to the surface as proof of your journey, but here's a catch: you cannot, in any way, anticipate your arrival at that point, you have to free fall, descend with a conviction or with no expectation or point of arrival.

You see, a terrestrial being would become more tense and agitated the deeper it descends, but that's not you - you're aquatic, remember? The ocean is your home, and the deeper you merge with it, the more relaxed you become. When the base plates or your alarm on your dive computer finally wake you up out of that reverie, then you grasp the rope with one hand - it's the only time you're allowed to touch it - you grab the tag, and your body swings around by 180 degrees. And now might be a good time to ask yourself the question: Why are you here? Why are you doing this? You know, why don't just stay up on the surface? And I'd like to have a crack at answering that question myself. And my suggestion is that a key word is "surface." "The disease of our times is that we live on the surface. We’re like the Platte River - a mile wide and an inch deep."
Steven Pressfield said that. Right now, all of us here, I suspect, are glued to the surface of the world - gravity glues, doesn't it? - and we're stuck on this two-dimensional plane that extends over hill and vale, over lake and sea, separating the solid and liquid from the gas, the incompressible from the compressible, form from formless.

This boundary, this interface, is where we spend our lives: I climb down from a mountain, I swim across a lake, maybe, walk through a forest on the other side, and not once have I departed from that boundary. So there's a good reason why we say, of course, "free as a bird" or "free as a dolphin," but we never say "free as a hedgehog" or "free as a giraffe." So in rare moments, we escape that surface to soar through the air, but we're always kind of dependent on something that's outside our bodies, like a glider, a parachute, or a set of skis to land on.

The only other way that we can escape the surface is down underwater. And swimming and other aquatic sports, they don't really cut it because you're always staying on that interface at the boundary level. And swimming - you're raising your limbs to take advantage of the fact they move quicker through the air than the water. Free diving is the only fully aquatic sport, where we're completely submerged below the ocean, enveloped in something other than gas and without a tank of gas on our backs. It's unencumbered immersion; it's the only true way to escape the surface. And it turns out below the surface is a pretty cool place to be, right? I mean, 95% of our planet's ecosystems are down there underwater; we evolved from the oceans 530 million years ago. It has seahorses, red-lipped batfish, dumbo octopi - everything you want.

But here's the thing: it's not just our planet that has a surface layer, we have this kind of surface boundary in our minds that separates the rational, conscious mind from the subconscious below, and we dispend most of our lives above that boundary in this ethereal, untethered medium of rational thought, while below, there's a quiet, deep well of subconscious. It has its own activity, of course, down there, but it all happens without our awareness - we can't see into it, we don't know what's happening, but things come out of it. We don't know how deep it is, but we've never been to the bottom of it. And we can dive into that subconscious sea in the same way that we would free dive into the physical ocean of our world.

Of course, the physical origin of our species traces back to the ocean below the surface, and in the same way, our minds have evolved from below the surface, from the brainstem up, adding parts and building above the surface into rational thought and awareness. So it's not just the free divers, then, who go below the surface, anyone who practices meditation or mindfulness or even takes mind-altering substances is taking trips below into that still sea. And sometimes I almost feel like a free dive. You know, I almost feel like I'm cheating or taking a hack or a shortcut because your environment in a free dive is already a still ocean. You know, a hundred meters down, you can't think about politics or laundry or whether you said the right thing. All of that belongs to a different world that you've left behind up there on the surface. You become stillness immersed in stillness, and in that void, what is revealed is, I believe, one of the most beautiful experiences: It's an awareness of presence and presence in awareness.

It's pure consciousness; it's the one thing that we may never ever be able to explain with science. No matter how deep you go, of course, you've still always got to come back up. And I left you guys hanging down there in the dark depths, about to tackle that long swim back up to the surface - sorry about that. But this is going to be the most physical part of the dive - you had that free ride down, and now you're going to have to pay for it on the way back up.

This is where it all begins: Have you gone too deep? Have you stretched that umbilical cord to the surface out too far and to the point where it's snapped in two and now you don't have enough oxygen to come back up? Stop. You need to stop that right there. Thoughts themselves are brainwave frequencies that consume oxygen in their creation,
and negative thoughts, they breed like gremlin rabbits until they swarm all over your mind. If you panic here and now, you'll consume all the rest of your oxygen in a flash;
instead, you can count the strokes, give your mind something to do in the same way you would give a baby a pacifier to suck on. One stroke. Two strokes. Three strokes. Three strokes - how many more strokes to go? No, don't start that either.

Again, you cannot have any expectation or point of arrival, there is only this stroke, this kick, this now, this now, this now… Suddenly, your thoracic muscles contract, expanding your ribcage - it's a involuntary breathing reflex, trying to suck air into your mouth, but your mouth and your glottis stay clamped shut while you're underwater, so no water passes; and instead, your diaphragm is yanked up under your ribcage - it's kind of like a punch in the gut, saying, "You need to breathe … soon." Don't look up though. You still won't be able to see the surface. And if you look up, you'll break your streamlining as well as stretch out your trachea, which is being kind of collapsed by the negative pressure. This is the most delicate and dangerous part of the free dive, so it's when your safety divers come down to meet you and escort you through those final meters.

The light is returning finally, and with it, so is your buoyancy, allowing you to glide for longer on each stroke as the air in your lungs re-expands. Finally, the surface comes into view, and for those last moments, you enjoy the sensation of flying through liquid. You're about to wake from this dream, from this journey below surfaces, below the waves and turbulence of thoughts, you're about to return from a realm of pure consciousness, and when you do, when you suck in that first breath, you will do so not just as a terrestrial hominoid returned to its element but also, equally, as an aquatic mammal coming up for air.

Take a breath now - taste it as if it were your first, and hold on to that awareness of the depths as you return to life above the surface. This is why I free dive.

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