Breath holding to improve Sac rate?

[Sas]

Phew....

There's nothing wrong with holding your breath whilst on scuba. I do it all the time to stay still to take a photo and to avoid scaring the fish. It's holding your breath when ascending that is the issue.

 

[paddler3d]

There's nothing wrong with holding your breath whilst on scuba. I do it all the time to stay still to take a photo and to avoid scaring the fish. It's holding your breath when ascending that is the issue.

Just say you 'hold you breath' by maintaining your lung volume by controlling your diaphragm and maintaining an open air way. It is easier that way.

 

[TSandM]

I doubt that free diving training will affect SAC rate, except in this way: If free diving training increases your tolerance for CO2 accumulation, it could result in a greater willingness to skip breathe and tolerate elevated CO2. As someone who appears to be extremely CO2 tolerant to begin with, I can tell you that's a recipe for a low SAC rate and a miserable dive. Although you can fool your CO2 receptors that control ventilation rate, you can't get rid of the CO2 headaches, the increased narcosis, or the post-dive nausea.

I have to be very careful to make sure I breathe ENOUGH. You definitely don't want to extend your gas supply by underventilating.

 

[Herk_Man]

I am learning to improve my breath holding ability for free diving and was wondering if it will have an effect on my Sac rate? before y'all go down a dark rabbit hole, no I am not holding my breath while diving scuba. I breath slow and deep.

With a little practice I was able to improve my breath hold duration from one minute to three, not much changed this was one hour of practice. I am considering what effect it will have on Sac. if any if I continue to practice.

would it be any benefit to practice breath holding before a dive? reduce heart rate, relax etc, however increase blood CO2? good? Bad? how long is this effect? is one longer than the other?

If you deny your body of the things it needs to maintain life, it is going to ramp up its efforts to bring those things in. Translation: You are going to breathe harder and your SAC rate is going to suck.

Even deep free divers actually over breathe before they dive to saturate their system with oxygen so they don't require as much as normal and can stay down longer and dive deeper.

That's the kind of exercise I'd go with if I were you. But I'm not you and I don't want to scare everyone on the dive boat so I'm going to have fun telling jokes and stories with the other people on the boat, jump in the water, and dive until my console says to stop.

So far I've never regretted that method. :blinking:

 

[dumpsterDiver]

So you are recommending that he hyperventilate immediately prior to a scuba dive to reduce his air consumption during the scuba dive?

 

[Sloth]

proper free-diving technique should not involve hyperventilation. Big difference between a free-diving breath up and intentional hyperventilation. Personally i doubt doing a free-diving breath up before the dive would help but who knows.

Like others have said the relaxation aspect of free-diving training can help as the key to good free-diving and low SAC rate is in your ability to be as calm and relaxed in the water as is possible.

 

[Trace Malinowski]

Try sending a PM to [user]TraceMalin[/user], he's an avid freediver and accoplished tech instructor who leaves in-depth informative posts. If you get an answer, please post and keep us up to date...

The OP, SailNaked, contacted me and I sent him a PM, but I thought I'd post a more in-depth answer to the board.

I doubt that free diving training will affect SAC rate, except in this way: If free diving training increases your tolerance for CO2 accumulation, it could result in a greater willingness to skip breathe and tolerate elevated CO2. As someone who appears to be extremely CO2 tolerant to begin with, I can tell you that's a recipe for a low SAC rate and a miserable dive. Although you can fool your CO2 receptors that control ventilation rate, you can't get rid of the CO2 headaches, the increased narcosis, or the post-dive nausea.

I have to be very careful to make sure I breathe ENOUGH. You definitely don't want to extend your gas supply by underventilating.

Lynne is correct. Those medical degrees sometimes come in handy.

Freedivers and competitive swimmers can often be CO2 retainers. Both athletes are used to performing with increased levels of CO2. While a freediver tries to remain relaxed and experiences CO2 build-up related to time, a competitive swimmer is working extremely hard in a race and every stroke taken with the face in the water without breathing is advantageous. Swimmer's motto: Swim fast. Swim hard. Breathe later.

Lung capacity is greater for males who are tall, those who are athletes, and those who grew up at high altitudes. Females and those who grew up at sea level have lower lung capacities. My lung capacity is higher than average - 7.8 litres. At 5' 11", I am not that tall, but the many breathing pullover exercises that I was coached to do as a teen when my body was growing may have helped expand the rib cage and allow the lungs more room to develop as coach claimed. However, being an athlete from the mountains, probably helped. While this benefits my freediving ability, when scuba diving, my RMV is higher. Strangely, Italian freediver, Gianluca Genoni, and I were both born on July 5, 1968 in the mountains. Kind of a joke, but since he grew up higher, is that why he can dive deeper?

While that helps in freediving to attain depth, my RMV sucks. Even after 27 years as a scuba diver, I may have an RMV of .7 or .75 in deco compared to the .4 of one of my buddies. Meanwhile, my breath hold times can be as much as 5:30. That was great back in the day, but that's an easy warm-up for some of today's competitors.

I just looked up the largest human capacities FYI and found this:

The largest human lung capacity recorded is that of British rower Peter Reed at 11.68 litres, roughly twice that of an average person. Unofficially, Grant Hackett, an Australian Olympic Swimmer, has a lung capacity of 13 litres.

Big lungs need gas. Since athletes have larger lungs, serious freediving training may actually cause you to use more gas during dives.

In diving classes, it is usually the 5' 0" tall, 86 pound female smoker that uses the least gas once she becomes comfortable with her scuba unit - leaving everyone scratching their heads as to why the Goth girl is beating all the jocks.

The relationship between lung capacity, volumes, and cardio-vascular efficiency could probably be answered better by someone, such as Lynne, who knows human physiology far better than I.

None of my freediving students, some eclipsing me by making constant ballast dives over 250 feet, or holding their breaths over 7 minutes, were any better or any worse on gas than you'd expect them to be based upon physical size and fitness.

What's more important is how relaxed you are while scuba diving. Freediving may help you to be more efficient, fluid, and comfortable underwater. If you are cozy at 100 feet without being able to breathe, imagine how much more cozy you'll feel having double tanks!

proper free-diving technique should not involve hyperventilation. Big difference between a free-diving breath up and intentional hyperventilation. Personally i doubt doing a free-diving breath up before the dive would help but who knows.

Like others have said the relaxation aspect of free-diving training can help as the key to good free-diving and low SAC rate is in your ability to be as calm and relaxed in the water as is possible.

While Sloth is essentially correct, the DAN conferences that I've attended regarding freediving breathe-up techniques, would find them all being forms of hyperventilation to some degree. Agencies and organizations such as Performance Freediving, IAFD, FREE, CMAS, AIDA, IANTD and my own PDIC, will teach various techniques that are all designed to relax and trick the body in some way. The classic hyperventilation act, as most of us think of it, of rapid inhalations and exhalations, actually spikes the heart rate prior to descent. Other forms of breathe-up may only be safer because they help lower the heart rate prior to the dive. Whether or not you trick your body's CO2 receptors, time and movement, and even an active mind, will burn more O2. As O2 is used, eventually you will reach a point in which you will blackout. CO2 warns us to take a breath. If a diver doesn't feel like breathing, he or she may stay too long underwater and suffer from anoxia before surfacing to breathe. However, divers who use "proper" breathe-ups are also the most likely to stem off the chest contractions that a diver fights as the CO2 sounds the warning bell. These divers, too, may blackout.

The classic "shallow water blackout" is when a freediver descends and the lungs and other air spaces are compressed with depth and increasing pressure. At depth, the partial pressure of oxygen will have increased and a diver may stay longer, especially if the CO2 level has been artificially dropped. As the diver returns to the surface, the pressure drops, decreasing the partial pressure of the O2 in the blood, and the lungs expand back to near normal volume, drawing more blood back into the tissues and further decreasing the O2 pressure. If that pressure gets too low, the diver will pass out.

The lungs can compress so much that eventually they should squeeze or collapse, but through training by progressively diving deeper, the lungs will actually create a blood shift and fill with plasma. That's my layman's understanding of the phenomena. I, and others, have suffered bloody coughing from thoracic squeezes early in the season of training or when we have not performed adequate warm-up dives. Yet, when trained up, injury doesn't occur. We have ways of simulating deep dives in shallow water by performing "negatives" in which we exhale to various degrees before diving. This should only be done under the training of a coach or instructor because you can be seriously injured in shallow water.

The most important training consideration is to have a spotter, preferably trained in freediving or dive rescue, to help you in case you black out in the event of a static apnea accident. Static apnea is when you hold your breath on or near the surface with the face immersed to practice breath hold times. Bag valve masks with O2 are better resuscitation. When freediving in open water, it is important to have a spotter and practice "one up, one down" lifeguarding in which one diver dives while the other observes until that diver surfaces and signals he or she is okay. It is best to wait and make sure your buddy is safely breathing before diving yourself. It is also important not to dive below the ability of your buddy to dive to rescue you.

Like Sloth pointed out, relaxation is the key - for both freediving and scuba diving.

It is possible to use the freediving technique of facial immersion prior to a dive to allow cool water across the face, temples and head to begin to trigger bradycardia, or the "mammalian diving reflex," in which blood moves from the extremities toward the chest, head and vital organs to help keep them warm. I actually have bettered my RMV/SAC during cave & training dives when I've been waiting for others. Placing one's face in the water and breath-holding and bubble blowing for 5 or so minutes prior to a scuba may help with gas consumption early in the dive. The extra gas most of us use in the beginning of a dive when getting used to the water, or ridding ourselves of pre-dive jitters, could be counted toward improved gas consumption using this technique.

That said, the more you learn to do as a diver, such as freediving, will only help to make you a better all-around diver by giving you skills, confidence and experience. It may also open up new avenues of underwater fun.

 

[mafiajoe]

There's nothing wrong with holding your breath whilst on scuba. I do it all the time to stay still to take a photo and to avoid scaring the fish. It's holding your breath when ascending that is the issue.

Sure,holding your breath a few sec while taking a pic is no problem.But holding your breath or skip breathing whilst diving can easily lead to a very,very dangerous CO2 build up.I'm sure you dont want to go there
And as for holding your breath when ascending....that's DOA

 

[mafiajoe]

Fitness is a bell curve with regards to air consumption. A very fit person typically has a higher % of muscle and muscle consumes more at rest than fat does. Also fat is an insulator so the very fit person gets colder if exposure protection is constant. That is much of what is going on with women vs men as well; lower muscle to fat ratio and better insulation (subcutaneous layer).
I use less air solo than when I'm not solo. I use the most air when I am guiding tourists, so I bought a couple Asahi 120's.

From personal experience I agree with this.I'm a pretty big guy:1.85/100kg.(I think that's 6.1f/220 pounds for you),I think i'm reasonably fit,go running 3 times a week,I used to go to the gym(for nearly 30years) and swim.My air comsumption is generally speaking always worse than smaller guys' and women's.
I also use less air when diving solo.

 

[Rhone Man]

My dive computer gives me my SAC at the end of every dive, and the biggest difference I notice is that when I am in good shape (ie. working out) the SAC rate drops noticeably.

If you are doing a lot of freediving, you are probably getting into good shape (unless you are already in great shape), so it probably does have an incidental benefit.

Just my wholly unscientific view.