Murat exhale video interviews

[sebastien murat]

If anyone is interested in seeing a couple of short videos on exhale diving (interviews really) a friend, Peter Schneider, did some shooting in Bali with me earlier this year. There's another video in there somewhere as well if you tune into this one.

[ame=http://youtu.be/f6VGsu7YVpQ]Sebastien Murat explains exhale freediving ... - YouTube[/ame]

Seb

 

[fcallagy]

Watched it Seb and its very interesting as is the whole concept. I guess now its time to experiment a bit. I have only ever done exhales in training statics when the DR wasn't kicking in for me so I would "force myself" through what I describe as unpleasant for a minute or so and then do normal inhale static. My concerns would be equalisation although I use the otovent now on empty lungs but would be interesting to play around now at depth on frc and the last 10-5m on the return, I have gotten into the habit of looking forward to the free ride back up.

 

[cdavis]

Interesting thing about "exhale diving" is the range of things you can do with it. Seb uses it as a path to extremes. I use it as an easy, relaxed way to reef crawl and stay down longer and with better comfort (also safer). Lots of other ways to use the concept.

Feargus, if you thinking about it as a style of diving you might go to, more or less permanently, start with something like 60 percent of a lungful and no deeper than 60 ft, maybe less. Adjust from there. Like Seb says, it is a style that takes practice, takes a while to see the large increases in dive time, and you have to keep doing it regularly to do much depth with it.

I might get to Ireland next year or two, will let you know.

Connor

 

[Azrael3000]

Connor, I'm a bit confused about the safety aspect of FRC/empty. In your post above you say it's safer, but I do distinctly remember other posts saying it is not as safe. Can you or anybody elaborate on this?

 

[cdavis]

FRC/empty: two very different things, at least for me.

Azrael, can't blame you for being confused. There is a lot of confusion/misinformation, etc out there about "exhale" diving. I'll try to explain.

Empty, all the way out: A good way to kick in your dive reflex fast at the start of a dive session when combined with very shallow, short dives. Also a good way to invite a blackout or squeeze if you do it wrong. I suspect that most of the bad experiences with exhale diving occurred when divers, particularly those who have not explored exhale diving carefully, pushed things. My personal experience with "empties" is that they get very uncomfortable very fast.

FRC, half lung, or similar is quite different and, as far as I know, is very safe from B0 when combined with a diving pattern that makes the first part of the dive basically a static. That is what I do. It carries a risk of squeeze if you are too aggressive about going deeper too soon (all too personal experience).

Some explanation of the physiology shows why FRC type exhale diving works. My pardon to Seb if this isn't quite perfect. With roughly half a lungful, you experience much less buoyancy variation when going up and down. Negative buoyancy comes shallower and the rest of the descent should be a slow drift. This gives time for your dive reflex to set in, aided by small lung volume and less space to store c02. The body goes into 02 conservation mode much faster, descent takes less 02 and creates less c02. After a minute+, reflex is strong, blood and 02 are concentrated in the core, available to the brain, but much less so to the muscles. Now you can exercise, swim, fight a fish, etc. The brain stays highly oxygenated, so its safer, co2 doesn't get to the core as quickly or in as high a concentration, so its more comfortable. In summary, FRC diving is more energetically efficient and more physiologically efficient. You burn less 02 for the same dive time and the 02 you have is concentrated in the core/brain.

Hope that is not too incoherent.

Connor

 

[Azrael3000]

So if I understand correctly there is sort of a sweet spot with FRC (assuming that you have the necessary training) which makes diving safer by having a more pronounced DR and increased relaxation even though having less air (in the lungs).

One more thing. If I understand correctly SWB is caused by oxygen (air) being removed from the blood in order to increase the volume of the lungs during ascent. So in case you dive on FRC the absolute change in volume is not as big, thus removing less oxygen (air) from the bloodstream during ascent and so reducing the likelihood of SWB. Does that make any sense?

 

[sebastien murat]

Kind of.

Without re-hashing it all over again, there's a whole bunch of threads looking at this, some by me, some by others, if you've got the inclination to go looking

 

[efattah]

If I understand correctly SWB is caused by oxygen (air) being removed from the blood in order to increase the volume of the lungs during ascent.

Sadly this is one of the biggest misconceptions and fallacies taught about freediving. The term 'shallow water blackout' somehow implies that it is caused by shallow water. In fact the diver who suffers 'shallow water blackout' would have blacked out even if he had never descended more than a few feet underwater. The blackout is simply caused by diving for too long and running out of oxygen (or brain energy, more precisely). Similarly the diver would eventually black out even if he just stayed on the bottom and never tried to go back up.

A good example is dynamic apnea, or swimming horizontally just below the surface. According to the classical explanation of shallow water blackout, a dynamic apnea swimmer should be able to swim forever just below the surface, and never black out, because the lungs never 're-expand'. Yet, the diver blacks out all the same.

The only difference depth makes is that it can slightly delay the blackout (compared to swimming just below the surface) because the increased pressure allows you to extract a few more oxygen molecules from the lungs.

 

[sebastien murat]

Sadly this is one of the biggest misconceptions and fallacies taught about freediving. The term 'shallow water blackout' somehow implies that it is caused by shallow water. In fact the diver who suffers 'shallow water blackout' would have blacked out even if he had never descended more than a few feet underwater. The blackout is simply caused by diving for too long and running out of oxygen (or brain energy, more precisely). Similarly the diver would eventually black out even if he just stayed on the bottom and never tried to go back up.

A good example is dynamic apnea, or swimming horizontally just below the surface. According to the classical explanation of shallow water blackout, a dynamic apnea swimmer should be able to swim forever just below the surface, and never black out, because the lungs never 're-expand'. Yet, the diver blacks out all the same.

The only difference depth makes is that it can slightly delay the blackout (compared to swimming just below the surface) because the increased pressure allows you to extract a few more oxygen molecules from the lungs.

Technically speaking it should be called hypoxia off ascent or decompression-induced hypoxia. Either way coming up aggravates the hypoxia.

 

[Azrael3000]

Eric, I maybe wasn't very clear in my statement. Clearly, hypoxia is the cause for the blackout. I only thought, that ascending would speed up the process of running out of oxygen as Sebastien mentioned just above.

 

[sebastien murat]

Correct: the problem is aggravated by ascending through the steep pressure gradient associated with shallow water. There was no flaw in you statement: ascending into shallow water causes SWB, whereas hypoxia per se is simply a result of breath-holding, like Eric pointed out. But, I know many instructors couldn't explain the difference, which is pretty shameful when some much is riding on it.

On a somewhat diffetent note, l'll be making available an altogether safe substance that I developed and can potentiate the DR in the next couple of months if anyone is intetested. Its especially suitable for those who cover up their face with hood and mask. Of course, if you're doing ratified performances it would be considered doping, since it alters the way oxygen is delivered/conserved, but by far the vast majority aren't doing that, so ...

 

[cdavis]

Now you got my attention. Details on this stuff??

Connor

 

[freedivinmike]

Hi Connor, I have a question regarding FRC diving. Is the breath up before a dive very similar to what you would do on full lungs and what about recovery times? Same rules as a full lung dive?

Mike

 

[sebastien murat]

Basically, it changes you perception to cold, but essentially only on the face (and some other sensitive spots) so that water on your face feels colder than it really is. Its been designed so that its highly effective at water temperatures from about 29C and lower. In other words it magnifies the DR as you go deeper. Cold air has an effect but it works much more effectively when your face is in contact with water (or sweating). That's because the substance is configured to be hydrophobic, turning inward towards the skin. This is ideal because the DR is strongest if you're face feels warm before being placed in water.

 

[sebastien murat]

I'm going to redirect this post

 

[growingupninja]

Basically, it changes you perception to cold, but essentially only on the face (and some other sensitive spots) so that water on your face feels colder than it really is. Its been designed so that its highly effective at water temperatures from about 29C and lower. In other words it magnifies the DR as you go deeper. Cold air has an effect but it works much more effectively when your face is in contact with water (or sweating). That's because the substance is configured to be hydrophobic, turning inward towards the skin. This is ideal because the DR is strongest if you're face feels warm before being placed in water.

This does sound really interesting. I still want an underwater HR monitor to do tests on myself. I can't be entirely conclusive without it but I think I experience DR somewhere else on spectrum than what many people are reporting; doing facial immersion tests I experienced no DR in water above 65F, but when I have done tests in a pool which is probably about 79F, pulse was in the mid-forties and blood O2 sat was 98% after swimming an extremely relaxed, full lung 50M dyn (very easy 55 second swim for me). Those numbers are typical of my response to cold water facial immersion. I don't think I typically experience ascent tachycardia because to do the test I had to stand, take off my goggles to see, dry my finger, then get a reading, all while maintaining the initial hold. When pool training though I do wear very low profile Swedish goggles. I should repeat using a dive mask and see what happens; doing facial immersion tests, my mask typically slices DR in half... To this end I made some pipe goggles but I find the EQ tube horribly obnoxious so I am going to integrate it into a nose plug so I can EQ it with my nose, the same as a regular dive mask.

 

[sebastien murat]

Getting reasonable results under gravity conditions or when your face feels as cold or colder in air than water is problematic. Of course once the CO2 build-up flushes your face with blood and increases your face temperature it works ok; your face is the only place that seems to dump excess heat, which helps increase tolerance of hypoxia.

 

[growingupninja]

Getting reasonable results under gravity conditions or when your face feels as cold or colder in air than water is problematic. Of course once the CO2 build-up flushes your face with blood and increases your face temperature it works ok; your face is the only place that seems to dump excess heat, which helps increase tolerance of hypoxia.

Could you elaborate on CO2 build-up flushing your face with blood? You are referring to the release of vasoconstriction at the end of apnea? Thanks.

 

[cdavis]

So the stuff makes the water feel colder on your face and fools the body into thinking its in colder water. Presto, stronger DR.

What a cool idea. I want some.

Connor

Freedivinmike: check your pms, so we don't hijack the thread.

 

[baiyoke]

Now subject is changing away from exhale, but I'll ask here, instead of making a new thread:


There's something I don't understand well, even though I have read a very scientific explanation before (perhaps too difficult for me).

Is it easier to BO when doing less-than-full/exhale/FRC breathholds???

Some say it is safer, fx Sebastion Murat in this video because of stronger DR as I understands it.

Others say it is easier to BO along the lines that less CO2 is building up, and therefore it is easier to reach blackout.

Now I know Sebastion is very much into benefits of exhaling in depth-diving. So just for a second, to try separate different contributing factors, how about just a regular static? It seems it comes down to STRONG DR vs. CO2 BUILDUP.

Are there different believes and experiences about wich is "safer"?

Or is there perhaps like someone mentioned a "sweetspot" in exhaling, an optimal degree/amount of both DR and CO2?