Fear the Squeeze
Posted By Peter Scott on 7 April 2003
Preventing Lung Squeeze in New Freedivers
The Polynesian and Ama divers appear to have learned that diving below --40m, the average depth where residual volume is reached for many people, is a dangerous undertaking not to be taken lightly. Or else they find what they need at shallower depths. Just because modern freedivers can dive much deeper does not mean that we should take that ability for granted.
Other unknowns also complicate the risk evaluation of going "deep." The function of the cardiovascular and circulatory system is tied to the pulmonary system. Changes in blood pressure, stroke volume, heart rate, and other variables may also increase the risk of pulmonary edema and intra-alveolar hemorrhaging. However, without specific proof, it is unlikely that freedivers will take these additional factors into consideration.
More research is needed to develop a guide to reducing the risk of lung squeeze, just as attention has been focused on blackouts. We still don't have a meaningful medical examination protocol for freediving. Most doctors have no clue how to examine freedivers on their way to a competition.
The freediving community also needs to gather statistics on barotrauma of descent. National freediving organizations (such as AIDA chapters) should keep track of athletes who surface with the symptoms of lung squeeze. I invite Philippe Afriat, the AIDA International physician at the Cyprus competition, to be on the lookout for such incidents and keep track of the depths inscribed, experience level of each diver, and severity of the injury.
Instructors who offer freediving courses should also consider making lung squeeze a part of teaching safety. To my knowledge, few address lung squeeze and how to minimize the risk.
In closing, I hope that freedivers will start to recognize barotrauma of descent as another important risk to actively minimize in the freedive training. I also hope that accomplished divers will recognize that the freedivers most at risk are their friends diving below --30m for the first time.
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