Post-dive breathing

[hteas]

I realize there are serious problems with hyperventilating before a dive, but what about after?

My thought is that if you want to get the CO2 down in a hurry, hyperventilate after reaching the surface. This would be more than the three breaths that Performance (and I assume other training groups)suggests. It would produce a stronger gradient to get rid of the CO2 faster, and allow you to get ready for the next dive sooner.

Anybody looked at this seriously?

 

[sgnips]

i think (this answer might not be as serious as you expect, but i try) you just need a few breaths to both lowering the co2 and raise the o2 in your lungs at the standard levels, as you can completeley change your full amount of air in 3-4 breaths

this way, lowering the co2 more than the standard via hyperventilating is just of no use

 

[trux]

The CO2 is not really a problem after a dive - in fact it helps the brain staying oxygenated and awake (thanks to the Bohr saturation curve shift), so you do not want to blow it out too fast. At least not before you are safe from the risk of a hypoxic blackout, which is typically the worst around 20s after surfacing. What you need, is fresh O2 and especially higher PaO2 that will help oxygenating the blood. And you also want higher blood pressure, since it drops rapidly after the surfacing. For this reason most competitive freedivers use so-called hook-breath (inhaling and shortly compressing your chest/diaphragm voluntarily). Look it up in more details in the archive.

On the other hand, I also know experienced freedivers who do not make any abrupt deep breathing after surfacing, and even no hook-breath - they claim that all of it represents unnecessary muscle work and tension that only increases oxygen consumption. I am not sure if they are right, but on the other hand, after seeing couple of Natalia Molchanova's completely relaxed surfacings, where she does not even appear to be breathing, I wonder if they are finally not right.

 

[trux]

this way, lowering the co2 more than the standard via hyperventilating is just of no use

Although you can renew the air in lungs pretty fast, most of the CO2 is not stocked in the lungs, but in the blood and other liquids, hence it takes quite a bit longer to get rid of it (although the level of CO2 in lungs is low). The term "hyperventilating" in this case is not well used, because if you ventilate more profoundly after an exercise (or a breath-hold), it is not hyperventilation by definition (hyperventilation is ventilating more than what the body needs). However, overdoing it voluntarily makes no sense either. Just let you body taking care of it itself - it can do it better than you You, instead of focusing on breathing, focus on relaxation, and get sufficient rest before you dive again. On my mind that's the best way to avoid both hypercapnia and/or hypocapnia.

 

[cdavis]

Hteas, good question, the kind of "out of the box" thinking that not infrequently leads to progress. I thought about this a lot and basically agree with Trux. I don't believe it would help, and might hurt. It only takes a few breaths to get 02 levels back up and blow off enough co2 to be comfortable After that, its just time required to recharge all the body's physiological systems before being completely ready for the next dive. Perhaps overbreathing soon after surfacing could speed that recharge, but continuing to huff and puff (hyperventilate) after the first couple of breaths seems more likely to slow recovery than speed it up(excess 02 consumption, bohr shift making 02 less available to the cells, plus who knows). That's something of a guess and I could be wrong, but it seems to fit what happens to me in the water. My after dive pattern is hook breaths followed by a few huff and puff breaths the knock down the co2, then go back to a very minimal breathing rate that keeps co2 levels relatively high until just before the next dive. That minimal breathup approach has been working much better for me than deep slow breathing or several other things I tried.

One thing that is not a guess is the difficulty in regulating such an approach. If you hyperventilate after you come up, when do you stop and how long do you wait before diving again? You risk building up a "reserve" of low c02 body(fluid) mass that has the same negative effects as hyperventilating just before diving. Timing would be tricky.

Connor

 

[azapa]

I think that the effects of hyperventilation on a dive would be long gone if you did them early enough in the recovery. Lets say a 4:00 recovery time (quite deep spearing dives). If you hyperventilated at 00:30 for 5 or 10 seconds, and then rested another 3:00 you would be fine.

Martin Stepanek (PFI too) call these "cleansing breaths" and they are to be done after the recovery breaths (hook breaths).

If I have done a really hard dive the above method (recovery for 10 secs, cleansing or hyperventilation for 10 secs, shallow breathing completely relaxed for 3:00) can help to get back into the zone. On the last minute of the shallow breathing its important to really feel if you are too fast or underbreathing. The precise point is hard to feel.

 

[hteas]

OK, what I didn't mention is that this came to me last Saturday, after an hour in +1C water. I really don't have a lot of body fat to keep me warm, so I am rather disinclined to breathe up for 4 minutes before the next dive. If I stayed still for that long after each dive, I'm afraid I'd become one with the ice trying to form on me during the surface intervals. So think on the edge.

I agree that I get comfortable rather quickly, 2 to 3 hook breaths and a couple of cleansing breaths, like I was trained to by Kirk and Martin. I'm just trying to stay alive in the interval between dives.

I'm wearing a 7 mm open cell suit with 3 mm vest and inner hood, and still get chilled rather quickly (and I'm sure it's not that I'm 61 :+

Trux, I guess you gave the best info. I still need to wait until at least 20 seconds after each dive to make sure my bp is stable, and that there's no delayed O2 problems-thanks

Howard

 

[Don Paul]

Great thread .... taking it all in. I dive alone allot so every bit of a edge helps.
Thanks guys.
Don.

 

[MikkoP]

On the other hand, I also know experienced freedivers who do not make any abrupt deep breathing after surfacing, and even no hook-breath - they claim that all of it represents unnecessary muscle work and tension that only increases oxygen consumption. I am not sure if they are right, but on the other hand, after seeing couple of Natalia Molchanova's completely relaxed surfacings, where she does not even appear to be breathing, I wonder if they are finally not right.

I think it could be more related just to the fact that she usually doesn't take her dives to the limit. Similar to Sietas, Stig and some other great divers. If you surface while you are still perfectly fine, it doesn't really matter how you breathe. You are going to be okay whether you do hook breaths, breath normally or even take only one breath.

On the other hand, hook breaths can be very helpful, if you are close to samba or having samba already. But if you're okay, it doesn't really matter. Of course, it's best to do hook breaths after every dive, because that way you'll do it automatically when you're on the edge.

When doing consecutive dives, I agree that it's best to let your body decide the rate of your breathing between the dives, so that you're not hyperventilating.

 

[azapa]

I think it could be more related just to the fact that she usually doesn't take her dives to the limit. Similar to Sietas, Stig and some other great divers. If you surface while you are still perfectly fine, it doesn't really matter how you breathe. You are going to be okay whether you do hook breaths, breath normally or even take only one breath.

On the other hand, hook breaths can be very helpful, if you are close to samba or having samba already. But if you're okay, it doesn't really matter. Of course, it's best to do hook breaths after every dive, because that way you'll do it automatically when you're on the edge.

When doing consecutive dives, I agree that it's best to let your body decide the rate of your breathing between the dives, so that you're not hyperventilating.

Mikko, Hook breaths are a great 'pre-programmed' training IMHO that should be done on all dives, even if they are limit dives or not. I always do them spearing in deeper water, even if I feel fine.

 

[Fondueset]

I dive in cold water alot - around 1 or 2c - I wear a 5 mil smoothskin out suit (less heat wicking in cold air) and sometimes a 1.5 vest. Long breatheups are just not practical in really cold water unless you are only doing a few dives. I just accept the fact that the breatheups and dives are going to be short - with lots of monofin sprints sprinkled in to stay warm. What you eat before a dive is a huge help too - but on balance at those temps its short dives.

In open water I like the small inhale/hold - then fast breaths for a bit - maybe 20 seconds - then a long, gradual slowdown before the next dive.

Doing 50 yard u/w laps with the mono in the pool I pretty much just pound air - trying to keep the intervals short - but thats not near my limit.

After a time you can feel if you are hyperventilated or not - I basically look for a very slight dreamy feeling in the head. I've never pushed it to tingling or anything like that. If I feel I'm over the top I do pauses at the top or bottom of each breath for awhile (depending on weighting - bottom is preferable)

 

[hteas]

Fondueset,
Obviously we're thinking along the same lines.
Dives start shorter and shallower than in friendlier climes, and get really short before it's all over for the day. I'm just trying to think of a way to extend it a little. I usually give up when I 1) can't hold the snorkel in my mouth, or 2) when i can no longer squeeze my fingers hard enough to clear my ears.
At the beginning of a day on the bay I tend to do cleansing breaths and then slow way down on breathing after a couple of hook breaths, and by the end I'm sounding like a locomotive in between dives, and still falling behind. : (
But bottom line, any training is way better than a winter with my ears dry.

 

[Fondueset]

The revelation for me in winter has been the monofin. In a pinch I'll do fin sprints. Normally I swim about 1/2 mile out to a dive spot in a series of underwater sprints - likewise back. So, after a few long dives, just before I start shivering - I sprint for shore and am all warm by the time I get there.

For food I use oatmeal with a date chopped up, sesame tahine and raw coconut oil. This gives me pretty good heat without resorting to garcinia or anything thats rough on the liver.

Also - a henderson ice mask saves a HUGE amount of heat. It's ridiculous what you lose through your face. I no longer use one because I don't like feeling like a submarine - but there is no doubt they save energy.

 

[hteas]

I eat oatmeal with dried fruit and coconut oil before diving. The problem is that if I eat within 4 hours I really feel it every dive (lead in stomach), so I try to waitwell over 4 hours after eating. With my metabolism I'm starving by then : o
The 2 mm underhood from Imersion I just got seems to help, but even so, the suit is awfully thin at 15 m.
what I really want is a suit like the experimental one a friend had in the mid-70s (except much more durable). Somebody tried making neoprene with little glass spheres instead of nitrogen bubbles. The suit didn't compress, but they didn't last long either. The little glass spheres crushed, and then the whole suit fell apart.

 

[Fondueset]

Oatmeal lasts me about 2 or 3 hours and im good to go after 45 minutes. Maybe don't eat so much and eat it sooner?
I dive in a 5 mil down to 2c or so, but i do work pretty hard and its usually under 2 hours.