your beautiful natural buoyancy compensator device

Inside each of us is a beautiful, personally crafted set of scuba equipment.  it didn’t really dawn on me until I started teaching, and began to compare a BCD (buoyancy compensator device/jacket filled with air) with lungs.


This came about during CESA’s.  Controlled Emergency Swimming Ascents,  students’ most dreaded skill, and instructors’ ticket to too many trips to the surface on an open water dive 2, 3 or 4. The idea is,  you’ve run out of air (I usually interject here, you will not run out of air, because I will be checking your air so much that it will become second nature to constantly check it yourself) and your buddy is either too far away from you, or not immediately available.  You must swim to the surface in a Controlled Manner, as in not too fast to give yourself the bends, while simultaneously exhaling air from your lungs and releasing air from your BCD.


It sounds complicated, but it’s not, given the science. Air compresses under pressure, and expands when that pressure is removed.  In this scenario, pressure=depth.  As we swim to the surface, the depth decreases, and therefore the pressure exerted upon our bodies decreases. All the air on our person at that point is expanding.  This is a fact.  Isn’t science awesome? Anyway, all students find it counterintuitive to let air OUT of their jacket as they are coming to the surface, because they think that means they’ll sink. Well guess what! If you are swimming up and letting air out at the appropriate pace, you won’t sink, and you won’t even have to swim too hard.  if you don’t let air out, what happens is: the air begins to expand quickly, and your jacket ends up rocketing you to the surface, until you breach the ocean like an Orca, or a Russian Submarine.  Not a great plan.  This will result in injury. But so easily avoidable.  Vent your jacket. Students remember this because I can remind them by holding up my LPI Hose and letting bubbles out myself.


What they forget is the BCD that is in their own chest. WE humans carry air inside of us in many different cavities. The most beautiful of these cavities  I believe is the human lungs.  In SCUBA we use our lungs naturally, and once we achieve that sugary sweet awesome spot of neutral buoyancy, we rise and fall gently with our inhales and exhales.  It really is a beautiful sensation, to be suspended so well and to be so in tune with your surrounding that the very breath you take controls your movement.  Just your breath.  It’s what yogi’s practice so hard for, and what scuba yogis find naturally in everyday use.  Lungs are the natural buoyancy control, and we don’t even need to lug them back and forth to the boat.  They sit inside us. Awesome! Lungs are naturally elastic.  They expand in size, and then shrink.  They are beautiful, pink, moist, elastic balloons in our chest.  But every day wear and tear affects them. And like a balloon, they can over expand and get injured.

og scuba equipment up in here.

So you must vent your lungs as you surface as well. This is easily achieved by exhaling during a CESA drill, or ascending slowly and breathing long deep breaths.  In and out, ascending slowly. All scuba divers are advised to service their equipment and to stay in good health.  Service your equipment annually.


With your lungs, service them daily.  Smoking can cause lungs to lose their elasticity and increase mucus production.  Neither are helpful for divers relying upon that elastic to expand and shrink.  Increased mucus production can cause middle ear problems (I learned this when I blocked my ears for weeks from a sinus infection). Smoking also causes “a reduction in the lungs’ ability to ventilate, which can reduce arterial oxygenation and consequently, exercise tolerance. ” and “With regard to Decompression illness, a 2004 study revealed heavy smokers tended to develop more severe symptoms of DCI than lighter smokers, who in turn developed more severe symptoms than non smokers.” (DAN, Alert Diver Spring 2012 “Dan Medics Answer Your Questions about Dive Medicine, pg 53-54) So don’t smoke (in general good advice for everyone), and use cardio to increase your lung’s elasticity and your tolerance for cardio vascular activity (strengthening a very important muscle, your heart).


breathe deeply good merfolk! xxmerbabe

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