bluebanded goby
Contributor
I just received the October issue of Undercurrent, a newsletter on dive travel. It includes a feature article on freediving headlined, "The Alternative to Scuba: Freediving Rises in Stature." This piece goes over various anecdotes about celebrity freedivers, quotes an article from New Scientist magazine on freediving, and generally treats the sport favorably.
It then spends some time on the physiological risks of freediving. Two of these I was previously aware of -- (a) shallow water blackout, and (b) a small but possible risk of decompression sickness among advanced freedivers who spend great lengths of time at depth without sufficiently long surface intervals, or also possibly under some conditions among those who freedive following scuba dives.
It then goes on to discuss pulmonary embolism as a risk of freediving. The article states, "Pulmonary embolisms are caused when pressurized air is trapped in a closed-off portion of the lungs. Freedivers generally ascend faster than scuba divers, without 'off-gassing.' So as ambient pressure decreases, trapped air can expand to the point of rupturing delicate lung tissue."
Now, I'm well aware of embolism as a risk in scuba if a diver ascends while holding his/her breath. I've seen some discussion by freediving authors about embolism risk if a freediver were to breath air at depth (from a compressed air source or underwater cave, etc) and then ascend while breathholding. But this is the first time I've run across any assertion that there is a risk of embolism to someone who breathholds throughout a freedive simply because of the rate of ascent. I did a search on the boards here and didn't see any other discussion about this. Is there any history of freedivers developing embolisms in their lungs because of rapid ascents when they haven't breathed additional air at depth? Thanks for any insight or comment.
It then spends some time on the physiological risks of freediving. Two of these I was previously aware of -- (a) shallow water blackout, and (b) a small but possible risk of decompression sickness among advanced freedivers who spend great lengths of time at depth without sufficiently long surface intervals, or also possibly under some conditions among those who freedive following scuba dives.
It then goes on to discuss pulmonary embolism as a risk of freediving. The article states, "Pulmonary embolisms are caused when pressurized air is trapped in a closed-off portion of the lungs. Freedivers generally ascend faster than scuba divers, without 'off-gassing.' So as ambient pressure decreases, trapped air can expand to the point of rupturing delicate lung tissue."
Now, I'm well aware of embolism as a risk in scuba if a diver ascends while holding his/her breath. I've seen some discussion by freediving authors about embolism risk if a freediver were to breath air at depth (from a compressed air source or underwater cave, etc) and then ascend while breathholding. But this is the first time I've run across any assertion that there is a risk of embolism to someone who breathholds throughout a freedive simply because of the rate of ascent. I did a search on the boards here and didn't see any other discussion about this. Is there any history of freedivers developing embolisms in their lungs because of rapid ascents when they haven't breathed additional air at depth? Thanks for any insight or comment.
