Fear the Squeeze
Posted By Peter Scott on 7 April 2003
One hundred and seventy-six freedivers from around the world are training for the 2003 Freediver Open Classic in Cyprus. Many of them, hoping to follow in the footsteps of world champions like Coste, Cruickshank, and Stepanek—with the knowledge that the minimum depth to be competitive is at least sixty metres—will push themselves and risk suffering from barotrauma of descent a.k.a "lung squeeze," an injury largely ignored in the freediving world.
When Enzo Maiorca descended beyond --50m and then Jacques Mayol surpassed --100m, the phrase "barotrauma of descent" was forgotten in the collective consciousness of freedivers. In the early days, doctors warned Maiorca that his lung would collapse under the pressure of the abyss. In simple terms, their model for the lung at depth was that of a container filled with gas compressed with each atmosphere of pressure until the residual volume (RV), or the minimum volume of lung gas needed to maintain oxygen and carbon dioxide exchange, was reached. Beyond that, they thought, the lung would stick together like a popped bubblegum balloon and suffocate the diver. What the scientists didn't understand was that blood pooling in the body's core allowed freedivers to go much deeper than the theoretical depth calculated by Boyle's Law.
We are all happy to imagine ourselves as dolphins or seals, one step ahead of science. We've got the blood shunt, we've got bradycardia, and peripheral vasoconstriction, and splenic contraction—we don't need the doom and gloom of physicians that have been wrong in the past. Even I remember a feeling of defiance when I put the -50m mark behind me back in 2001. However, the lack of scientific certainty does not mean that diving below your residual volume is risk free. I did not reach Maiorca's science-busting depth unscathed.
My Personal Experience with Barotrauma of Descent
In 2001, training for the Canadian Nationals, I wanted a spot on Team Canada. The weekend before the competition, I increased my personal best by eleven metres in one day, from -37m to -48m. At the time, I was not aware of the stress this sudden plunge downward had had on my lungs. Five days later, I announced --46m and made it, like a beginner, nervously sprinting the whole way. For about an hour following the dive, I spat blood and was wracked with body buckling coughs, wheezing and rales.
I made Team Canada, but I suffered lung squeeze at least three more times. I was going too deep too fast. I decided to start all over again at --35m with a longer warm-up, negative pressure dives of increasing intensity, and even repeated neutral-breath dives up to -25m. I increased the depth only after reaching a "safe" depth several times without any symptoms at all, gradually inching my way downward. Before Ibiza, I made several dives to over -50m without any symptoms. I was pretty happy that my precautions worked.
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