Mr T's Wild Freedive

[Celt]

@mac64 Like I I said long ago in this thread my kid does it too on the shallow reefs it is not a big deal, But once you start going past 40 feet it is.

Hence why a hookah is relatively safe. You don't even reach your negative buoyancy really until 20 feet.

T I really do enjoy your posts but I just couldn’t agree with some of the stuff you post. If my son did some of the stuff I did in my teens I’d break his neck. We’ve moved on and the risk of injury is unnecessary.

 

[tridacna]

So your suggesting that people dive to 70 feet and take a breath off of a regulator?

"You're" NOT "your".

"Take a breath from a regulator" NOT "Take a breath off of a regulator".

Do you actually read the drivel that you write?

 

[IncreaseMyT]

Do you actually read the drivel that you write?

You obviously do.

 

[IncreaseMyT]

Interesting, from the same article, this doctor suggests that hyperventilating actually helps you reduce your oxygen consumption, which would be yet another contributing factor to increasing your chances of hypoxia if you take a breath off a reg at depth.

These are not just any doctors either, a group a doctors put together by a Command Surgeon in the Navy.

And finally, I would also like to say that if you hyperventilate, you increase the oxygen stores, as was mentioned here, so you have a bigger margin, but you probably also reduce your oxygen consumption, because you are very much more relaxed. In fact, those contractions can, at least for me, they cause a little effort. It is painful. If you completely relax, you reduce your oxygen consumption. So you probably, if you hyperventilate, you actually push the duration forward even more. Not to say that hyperventilation is safe, but it is a good point to have that you might need to reevaluate how we perform the safe training dives.

LIMITING FREEDIVES TO 60 SECONDS FOR SAFETY

 

[saxman242]

That's assuming that breathing off a regulator brings you out of a relaxed state, which I'm not sure there's any evidence to say one way or the other.

 

[IncreaseMyT]

That's assuming that breathing off a regulator brings you out of a relaxed state, which I'm not sure there's any evidence to say one way or the other.

The whole reason you are more relaxed and using less 02 is because you hyperventilated before taking a breath, if you don't do that, your breath hold will be shorter.

Also remember your fighting an extreme buoyancy change and using more 02 that way as well. Oh did I mention you only have a half a breath?

So it is not that hyperventilating increases your chance of a shallow water blackout, it is that hyperventilating gets you closer to your max breath hold, thereby increasing your chance of a blackout. Which further substantiates my point that taking a breath off a reg will drastically reduce the amount of time you could stay down, both through less oxygen stores, and increased oxygen consumption.

 

[IncreaseMyT]

This ALSO further substantiates my reasoning for a shallow water blackout to be a concern during a CESA. Now that we know shallow water blackouts are in fact caused by a lack of pressure, and oxygen. And being on scuba you are going to have less oxygen stores, IE less time before blacking out.

 

[RyanT]

So it is not that hyperventilating increases your chance of a shallow water blackout, it is that hyperventilating gets you closer to your max breath hold, thereby increasing your chance of a blackout.

Let's substitute a few words here...

So it is not that "driving fast" increases your chance of a "crash," it is that "driving fast" gets you closer to your "inability to stop," thereby increasing your chance of a "crash."

 

[IncreaseMyT]

Let's substitute a few words here...

So it is not that "driving fast" increases your chance of a "crash," it is that "driving fast" gets you closer to your "inability to stop," thereby increasing your chance of a "crash."

Are you still trying to say that hyperventilating increases your chance of blacking out and that is not due to lack of oxygen or pressure? I have clearly proven that not to be the case.

LIMITING FREEDIVES TO 60 SECONDS FOR SAFETY

"Dr. Qvist et al. (6) in 1993 studied arterial blood gases during immersed, exercising dives performed by five Korean Ama divers. Once again, these divers did not seek to achieve maximal breath-hold times, with their average dive being approximately 0:30 min:s. The investigators then requested that the divers hold their breath as long as possible for a series of 37 dives. The mean breath-hold time on these dives was found to be 1:02 min:s with a maximum time of 1:24 min:s. The PaO2 after this longest dive was 33 mm Hg and the arterial oxygen saturation was 59%. The authors stated in conclusion: “In the current study, dives that lasted longer than 55 s were associated with large and potentially dangerous decreases of arterial oxygen pressure and content.”"

 

[saxman242]

Are you still trying to say that hyperventilating increases your chance of blacking out and that is not due to lack of oxygen or pressure? I have clearly proven that not to be the case.

Hyperventilating suppresses your natural drive to breath, so yes, it increases your chances of blacking out, even though the cause of blacking out is due to lack of oxygen.