Question about intense ventilation before dive

[Lars Johnson]

Hi

I visited a dive center in the Caribbean and they where doing some
weird stuff.

I was on scuba (felt safer) but there was three guys smoking dope and
doing short shallow skin dives without tanks. The "instructor" urged
them to ventilate for quite a long time before the dive.
"It is safe if you limit the dive to 1 minute" he said. I argued some
with him, but I didnt know what arguments to use. I have heard that
you get blackouts if you hyperventilate. Is that true. And what about
this "one minute thing", what did he mean?
Check the dive center (cozy place, funky dudes
Ganja Diving - A way of living


Lars Johnson

 

[lambe]

Hey Lars! I'm not an expert on this but I thought I would share the things I do know.

Hyperventilating reduces the amount of CO2 in your body. With other words the urge that tells you to breathe, will not kick in as soon as it "should" have. The dangerous part is that you might blackout because you need breathe but you can't feel the urge to breathe. Get it?

"It is safe if you limit the dive to 1 minute." Personally I think he means that everyone basically can hold their breath for one minute. There for it's safe to hyperventilate.

Most of the people I've spoken to about hyperventilating here on the DB forum is against it and so am I.

Correct me if I'm wrong but this is what I've learned.

 

[Lars Johnson]

Hmm makes sense, but this guy claimed that that is not an issue as long as you only stay under 1 minute. But I guess this is minor details when these guys are diving high on marijuana while freediving.

 

[trux]

There are some very good threads about hyperventilation here on Deeper Blue, so to avoid repeating all the facts, and omitting some of them, I suggest that you search the forum archive for the term hyperventilation.

Basically, you are right, and the instructor was a great moron. Teaching beginners to hyperventilate is the worst ever advice, and leads to many avoidable deaths every year. Not only it suppresses the urge to breathe, but it also reduces the hypoxic tolerance (it means you will black out earlier than without the hyperventilation). And additionally, the 1 min limit is absolute nonsense - first of all when you want to stay under water just for 1 minute, you do not need to hyperventilate. And when you hyperventilate for the increased comfort, and feel still comfortable at 1 min, you will push further and further, until you black out without any warning signal. And then, when you hyperventilate excessively, you can black out right at the beginning of your breath-hold, just a few seconds after you start it.

The conclusion is, the instructors are real morons and would deserve that someone sues them for such deadly advices.

 

[x_yeti]

Yes, I dived with these guys once. It was a blast! The dive instructor said that the ganja helped increase the number of fish and the intensity of the colour. He was right.

Only problem with diving with these guys is that they were soooo smoked up that they kept getting their dates wrong which made it almost impossible to get an organised dive scheduled.

 

[Lars Johnson]

I can't say I am part of the "moral majority", but I´m not a drug liberal either, so this thing with mixing drug use with diving is a bit "over the top", being legal or not.
His diving was pretty impressing though, this dutch guy swam circles around us on scuba, even though we were down on at least 50 feet. But wierd with all the weed smoking on the boat. Not your average day at sea so to speak.

Lars

 

[Simos]

Sounds like ganja freediving is a topic only covered in the ***** courses
Posted via Mobile Device

 

[Bill]

One small note. I think that the one minute thing comes from the swimmers and that many coaches now use it as a limit for anaerobic training.

 

[Simos]

Makes no sense to me
Posted via Mobile Device

 

[cebaztian]

In an article in DAN magazine some years ago an Italian Apnea scientist ckaimed that all free dives that was limited to 60 seconds is safe no matter how much you hyperventilate before.

Regarding mixing marijuana and breath holding as mentioned at Ganja Diving - A way of living I thinkl it is bull***** as far as I know cannabis is not officially legal on Jamaica, but these guys might be operating in a grey zone.

Sebastian

 

[Mullins]

In an article in DAN magazine some years ago an Italian Apnea scientist ckaimed that all free dives that was limited to 60 seconds is safe no matter how much you hyperventilate before.

Hah. You could do a 30m (or more) spearfishing dive in that time.

Site is hard case. April fools joke?

 

[trux]

In an article in DAN magazine some years ago an Italian Apnea scientist claimed that all free dives that was limited to 60 seconds is safe no matter how much you hyperventilate before

Unless it is your traditional April fool, Sebastian, I wonder how someone can claim something like that, when it is very well known that hyperventilation games are a rather common cause of death among children. And that's on dry land, without prolonged breath-holds, without the added risk of blacking out underwater, and without the added risk of depressurizing during the ascent. Some sources claim 1800 deaths from choking games in the USA within 10 years. That's not verified, and may be exaggerated - in Wikipedia they speak about at least 82 deaths in the USA attributed to the hyperventilation games in the years 1995-2007. And they also explain that the trigger that initiates the syncope at the kids is often a "bear-hug" from a friend, that approximates the Valsalva maneuver, causing vagal stimulation (see the paragraph Self-induced hypocapnia). In other words, when diving, you do not even need the bear-hug. Already the duck-dive can trigger it, and when not the duck-dive, then the Valsalva maneuver when equalizing.

 

[cebaztian]

Well this is getting a bit Off Topic.
I do not remember the details of the article.
I just remember that a scientist, probably Italian, claimed to have solved the problem of death in freediving: NEVER STAY UNDER LONGER THAN 60 SECONDS. Because he had proven that O2 levels NEVER could go to critical levels within 60 seconds. I wrote the magazine claiming that I could get a BO within one minute if I hyperventilated and did apnea under heavy workload. The scientist was not impressed by that.

 

[trux]

Did they write the article also on the 1st April?

 

[cebaztian]

Did they write the article also on the 1st April?

No, but find and read the article yourself and get the details.

Sebastian

 

[Simos]

Out of interest... Anyone know of any cases of freedivers that blacked out during the descent as a result of valsava?
Posted via Mobile Device

 

[Walrus]

Teaching beginners to hyperventilate is the worst ever advice, and leads to many avoidable deaths every year. Not only it suppresses the urge to breathe, but it also reduces the hypoxic tolerance (it means you will black out earlier than without the hyperventilation).

I agree teaching beginners to hyperventilate is not good advice, but could I ask where people keep getting the idea that it actually reduces your safe bottom time ?
Perhaps it does for some people, and for others it doesn't, or if it does it's only a small difference ?

I know in my case it doesn't make that much difference, it get's harder to judge when to come up vs actual bottom time, distance, depth etc. I have seen quite a few top freedivers using very agressive breathe ups and set world records doing them. For depth diving I started using more hyperventilating because I have a greater fear of Narcosis then I do about blacking out on the surface for deep dives. I totally agree it effects your judgement and more likely to push your limits with lower CO2. Has anyone actually done some comparisons of dives/ breatholds with different breathe ups ?


Cheers,
Wal

 

[Walrus]

The Ganja diving website is hosted on a Dutch domain, it is legal in the Netherlands.

 

[Simos]

Hi Walrus
Hyperventilation doesn't of course mean that you can't do a great dive but it does make it more likely to black out.

I am sure you can find lots of info on hyperventilation but in short, hyperventilation does more than just lower your co2 (which obviously can lead to hypoxic blackout without warning).

Low co2 makes blood alkaline which increases the affinity between haemoglobin and o2 - this means that o2 will not offload as easily to tissues.

It also decreases the blood flow to the brain (cerebral vasoconstriction) thus reducing o2. In fact if you hyperventilate very aggressively it's even possible to BO while still breathing!

There is also another effect: if you HV you are essentially conserving less o2 as if I am not wrong it's the high co2 that instigates contractions and lowering of the heart rate...
Posted via Mobile Device

 

[cebaztian]

The Ganja diving website is hosted on a Dutch domain, it is legal in the Netherlands.

Hmm, as far as I know not in Jamaica, so I dont know how they get away with it. And if you would take your last breath (before apnea) from a joint, how much O2 would there be in your lungs?