Freediving, Embodiment and Humanity

In this post I'd like to utilize my experience with freediving as an excuse to talk about a bunch of seemingly contrasting qualities and emotions, which together — I feel — illustrate some deeper aspects of experiencing humanity. For me, at least, freediving has turned out a surprisingly useful tool in this endeavor.Freediving is a curious activity. You take a deep breath and off you go — a few tens of meters under water: 30, 40, 50m, maybe more if you're really good. Or maybe just 20m deep, but for a more relaxed fundive, enjoying flying in 3D space among rocks, coral reef or wrecks. We don't need all those clunky tanks with air or other gases, which scuba divers are so dependent upon. And, unlike scuba diving, we're not limited by ascent rates, meaning we can travel vertically as fast as our fins (or scooter!) let us do that. We dive silently without exhaling bubbles and without those Vader-like breathing noises, so marine animals are not scared of us. We're sleek and free. Unified with the environment and ourselves. Pure freedom.Urge To BreatheBut there's a catch. Breathing is our most primordial reflex. Try holding your breath now — start your stopwatch and see how long it takes for you to feel the first symptoms of what we call Urge To Breathe (UTB)?Now imagine you are forced to remain breathless for another minute or two, or more... How would you describe the feeling?The UTB sensation can typically be reduced to a few more basic symptoms: contractions of the diaphragm, sensation of heat, feeling of pressure on the chest, urge to swallow, or feeling of pressure on our glottis. These elemental symptoms are interpreted by our brain's higher-level subsystem(s) as a pressing need to resume breathing.Interestingly, when we learn to "decompose" this high-level feeling into the more basic bodily reactions, UTB usually gets a bit easier to tolerate. At least for a bit. My understanding of this phenomenon is that our brain is alerted by these bodily reactions, rather than directly by the CO₂ sensors. This is perhaps similar to how a bit of liquid on our cheeks might make us feel sad, because our brain thinks we're crying.

But once we understand the liquid comes from the eyedrops, not our tears, the feeling of sadness vanishes.Nevertheless, the longer we push beyond the first UTB symptoms, the more difficult it is to tolerate the situation. Suffering starts spreading all over the mind…While cells go about their whatever-they-are jobs, they burn oxygen (O₂) and produce carbon dioxide (CO₂) as a side product. CO₂ is then collected by blood, transported back to lungs and expunged when we exhale. And, quite surprisingly, we are actually sensitive to the buildup of CO₂ level in our organism, rather than the dropping level of oxygen. Interestingly, in most humans1, the critical CO₂ threshold that triggers UTB symptoms comes very early, much before the oxygen level falls into the dangerous territory.2Our nervous systems are very conservative, in other words. If you are a generally healthy individual and have a pulse oximeter nearby, you can make an interesting experiment. Sit comfortably, put the oximeter on your index finger, then inhale and hold your breath. Keep holding it until you start feeling the first symptoms of an urge to breathe. At this moment notice the oxygen saturation (and resume breathing).3In most healthy humans, the oxygen saturation will still be at a very high level, above 95% say. This means there is still a lot of oxygen in your blood. And yet, since you already started feeling the UTB symptoms, your nervous system already thought it appropriate to trigger an alarm to resume the breathing.How nice would it be to "hack" one's own autonomous nervous system so that it was a bit less anxious…I already hinted at one technique that might be useful — consciously focusing on what we feel in the body. Others exist. In general they fall into — or can be applied — in two broad approaches. One is through suffering, while the other through finding bliss and pleasure in the act of freediving. We will get back to this in a moment.For now, I will just note that there is an obvious tension here between a desire to stay underwater longer (because it feels good) on the one hand, and the desire to resume breathing (because it feels bad once we move past the first symptoms of a UTB).Pressure And EqualizationBut breath holding is, surprisingly, not the only challenge in freediving.

In fact, as far as depth diving4 is considered, the breath hold times are typically not the prime limiting factor. At least not at the beginning of one's journey…When we dive deep, many tens of meters underwater, the pressure of the surrounding water rises very quickly. For every 10 meters of depth we get another 1 bar of pressure (or 1 atm). This means that at 40m (130 feet) the surrounding pressure is 5 times of what we experience on the surface. How is it that this pressure is not crushing us?It actually does crush us, only that our human bodies are quite good at withstanding such crushing!The tissues that make our human body are liquid and thus incompressible under pressure (they just transmit pressure without changing volume themselves). But then there are also a few air-filled spaces inside us, such as the lungs and connected chambers. When the surrounding tissues start transmitting the compression forces from the water outside, the gas inside these spaces will get compressed.5 The compression stops when the gas pressure reaches equilibrium with the external water pressure.6So far, so good! But there are a few outliers among these air-filled cavities: the middle ears, the sinuses, and (sometimes) our diving mask7. These spaces require special attention from a freediver — the middle ears and the mask would not automatically equalize, while sinuses might just refuse to equalize even in case of a mild infection.The middle ear(s) equalization is a huge topic in freediving. Various surprisingly sophisticated methods have been invented/discovered to let humans ensure that the pressure within their middle ear remains in balance with that of the water outside. Otherwise, the eardrum would be ruptured by the mounting pressure of the water outside. That would be a serious injury, causing immediate loss of spatial orientation, in addition to loss of (or significant degradation of) hearing.8These equalization techniques are really about obtaining some kind of mastery in feeling, relaxing and controlling our bodily organs within the larynx and pharynx.The Freefall EmbraceWhen the lungs are compressed by the mounting pressure, the buoyancy of the freediver decreases. At some point we can stop moving the fins and gravity will do the rest. We will be falling in what we call freefall. Perhaps one of the most amazing experiences in freediving.But there is also a flip side to the lungs compression.

We should be careful not to tense our intercostal muscles or stretch our ribcage at depth, as otherwise an injury called lung squeeze might occur. A good analogy here is to imagine a plastic bottle, one made of very hard plastic. We fill it with air and submerge underwater. As we move down, the pressure will be crushing the bottle walls. The harder the plastic, the harsher the damage. Now imagine an extra soft bottle, or plastic sack for water. This will be gently compressed without any damage.So, the best way for a freediver to withstand the enormous pressure at depth is to relax any muscle tension in the ribcage (and also in the throat to allow smooth equalization). This usually requires more than mere muscle control mastery. It requires a change of mental attitude — instead of trying to withstand the pressure, we should let the water embrace us. Surrender to the environment.This surrendering-to-water attitude goes well with the overall freefall experience. In freefall, with eyes closed, body relaxed, we let go of everything: the control of trajectory, the control of time, the anticipation of hitting the bottom plate (the end of the rope).9 The time perception changes. 30 secs can feel like 5. A well-performed freefall feels great. But we can also easily ruin it. Tensing muscles. Letting anxious thoughts sneak in — Am I free-falling fast enough? How much longer? Will I have enough strength (oxygen) to work my way up? What the hell am I doing here?The BodyWe feel and appreciate freediving through our bodies. We feel the 3D space, the movement. We feel the water on the face, the pressure on the chest (the water embrace), the heart beating. We feel contractions when the urge to breathe comes. We feel panic. We feel relief. And satisfaction. And happiness.Freediving requires that we come to terms with our body. That we learn to feel it, relax it, and know subtle ways how to operate it. Freediving is a journey into ourselves, as seen through the perspective of our body.How different a perspective that is from the one prevailing among software engineers! There we often take the view that the body is just a necessary implementation detail, one that enables our minds to roam around the environment (e.g. computer conference floors) to meet like-minded humans (not like-bodied!)

to facilitate information exchange. Or, more radically, simply an interface connecting our brains with keyboards and monitors of our beloved computers…What is really interesting, however, freediving combines this subjective, non-intellectual perspective with an objective metric for our performance. This metric is, of course, the depth, expressed in meters, to which we are able to dive. You just cannot dive to 40 meters, say, if you cannot feel and relax your body well enough. The effects of the water pressure would be just too strong. So, freediving is like meditation, except you cannot cheat.I mentioned above the two contrasting approaches — through suffering (the "red" path) and through enjoyment (the "green" path). One teaches your body to ignore the stress signals (CO₂ level, pressure, darkness). The other approach concentrates on the amazing side of the experience: the joy of being in the 3D space, the delight of the freefall, the intimacy of the feeling of your own heart beating, the embrace of the water, you being part of the environment.Imagine you're standing in the middle of a busy city center. Tall buildings, crowds of people, cars. It's a hot summer day. You have nothing with you — no water bottle, no earbuds and your phone ran out of battery. Understandably you might feel anxious in such a situation. But you can try to change the attitude. Stop resisting. Imagine the city as a big symphony in which you also now play a part. The sounds are the music, not unbearable noise. The environment embraces you. You become part of it. Dissolving into it.But I actually suspect this dichotomy might be an over-simplification. In fact some combination of both the red- and green-paths might be needed. Most likely it's a spectrum. I just prefer to be closer to the green end for my freediving, but I understand some top competitive athletes might enjoy being at a different point on that spectrum.Blacking OutWhether you take the red or the green path, freediving is still a dangerous activity. When oxygen level drops below some critical threshold, the diver loses consciousness. This is termed a blackout. If there is no one to help a person who experienced a blackout, this person will die in the following minutes.