Freediving after scuba diving

[DiverDan1975]

I am sure this is common knowledge amongst the majority on this board, but I just read an article discussing the death of a diver who decided to freedive a couple of hours after a day of scuba diving and died of complications related to air embolism. Pretty scary. It makes sense physiologically as to why this is bad practice. I just felt the need to post in case any others would be tempted to freedive one afternoon after a day with the tanks. As we have been taught in our courses, we should refrain from strenuous exercise for at least 6 hours after taking a nitrogen load from a day of diving.

 

[scubadada]

I am sure this is common knowledge amongst the majority on this board, but I just read an article discussing the death of a diver who decided to freedive a couple of hours after a day of scuba diving and died of complications related to air embolism. Pretty scary. It makes sense physiologically as to why this is bad practice. I just felt the need to post in case any others would be tempted to freedive one afternoon after a day with the tanks. As we have been taught in our courses, we should refrain from strenuous exercise for at least 6 hours after taking a nitrogen load from a day of diving.

Arterial gas embolism or decompression sickness? I would suspect the latter if the freediving was shortly after scuba diving.

 

[Eric Sedletzky]

Arterial gas embolism or decompression sickness? I would suspect the latter if the freediving was shortly after scuba diving.

Could have been both.
You pack a full lung of air then dive down, pressurize, then ascend and depressurize. Some already saturated tissues in the lungs get shaken up releasing bigger bubbles on the way up without an exhale (freediving) and you have more gas expanding than the tissues can handle and you get a tear.

 

[OTF]

Yup, don't do it.

Though like all bad things, there are levels of bad. Do a single shallow recreational dive in the morning, and go snorkeling in the evening with a few casual dips below the surface? Probably going to be fine. Do a serious deep dive then an intensive freedive session pushing your personal best depth? Going to have a bad time.

 

[Nick_Radov]

Arterial gas embolism or decompression sickness? I would suspect the latter if the freediving was shortly after scuba diving.

The supposed mechanism of action is that after a scuba dive near or past the NDL, most of us have at least some bubbles in the bloodstream. Under normal circumstances those get trapped in lung capillaries and resolve over a period of several hours without causing any significant tissue damage. But free diving without an adequate surface interval can then cause those bubbles to compress down enough to pass through to the other side of the circulatory system. Then on ascent the bubbles expand back to their original side, potentially enough to cause ischemia. This makes some sense physiologically, although I'm not sure whether it has ever been experimentally verified.