blue hole?

[Bombay High]

I watched both those videos the other day, and was totally blown away. The thing that gets me is, it's so lonely down there. He just goes straight down and down and down, into the blackness. Very scary.

My wife said she watched a similar video of a woman who on rising from the bottom suddenly went limp. The scuba divers swam to her and brought her to the surface, but were unable to revive her. Presumably she blacked out (and then of course drowned).

There are 2 causes of loss of consciousness in free diving--one deep and the other shallow. But I can't remember what they are.

I've read that the trick to free diving is to learn to ignore the urge to breathe. Sounds unpleasant. I'll take scuba.

Matt - contrary to popular belief, freediving is a very technical sport - just not with hardware.

Shallow water blackout is a huge danger. That happens when as you ascend the PPO2 drops so low that it is too hypoxic for you to maintain conciousness.

These are highly trained and supremely gifted and driven athletes

 

[FPDocMatt]

I see it now. Had my "show signatures" turned off. Sorry.

 

[FPDocMatt]

And I think the other one is caused by excessive hyperventilation, but I don't know why.

 

[DandyDon]

Read my signature

Sounds nice. Not always true tho. :sad:

I see it now. Had my "show signatures" turned off. Sorry.

Now where's the fun in that?

And I think the other one is caused by excessive hyperventilation, but I don't know why.

I think that hyperventilating is often related to shallow water black out. I knew about the former from playing passout games as a dumb kid when I started untrained free diving, but not the latter. See Shallow water blackout - Wikipedia, the free encyclopedia

This article addresses the other Deep water blackout - Wikipedia, the free encyclopedia and seems to confuse the two, but then it clarifies the differences, I guess. Actually, it seems like we generally use the wrong term in our discussions of breath hold accidents.

• Deep water blackout occurs as the surface is approached following a breathe-hold dive of over ten metres and typically involves deep, free-divers practicing dynamic apnoea depth diving usually at sea.^[3] The immediate cause of deep water blackout is the rapid drop in the partial pressure of oxygen in the lungs on ascent.

• Shallow water blackout only occurs where all phases of the dive have taken place in shallow water where depressurisation is not a factor and typically involves dynamic apnoea distance swimmers, usually in a swimming pool.^[4] The primary mechanism for shallow water blackout is hypocapnia brought about by hyperventilation prior to the dive.

This confusion is exacerbated by the fact that in the case of deep water blackout hypocapnia may be involved even if ascent is the actual precipitator.

 

[RonFrank]

"The Sept. 24 death of this St. Petersburg Catholic High graduate — a fit and experienced diver — offered a glimpse into the little-known world of free diving, a growing phenomenon that teeters on the edge of tragedy.

Over the last five years, free diving has gained popularity among Florida fishing enthusiasts and thrill-seekers. Without air tanks or heavy equipment, a diver can stalk fish more easily.

But the breath-holding technique carries a potentially fatal risk. A free diver can suddenly experience shallow-water blackout, a condition that causes the diver to faint. "

Deadly risks lurk behind the thrill of free diving - Tampa Bay Times

This is just one of many articles on free diving. It appears risky, but the actual numbers are illusive. One thing for certain, free diving pros die alongside the amateurs, so the risk is real at all levels.

 

[RonFrank]

More on Ichetuckneesprings Blue Hole:

Welcome to Florida State Parks

Looks like a cave diving spot for sure. I have traveled extensively in FL, but have never been to Ichetuckneesprings.