Some static questions.

[Ol Dirty Diver]

To any of the knowledgable apneists, here are some questions of mine that arose recently:

• I notice that when perform deep breathing, my heart rate surges up (from ~50 -> ~70), obviously due to the muscular activity involved in deep breathing. When I did my first statics I did very deep breathing throughout my preparation phase, like I do when I freedive, but now I realize that this may cause my heart rate to rise unnecessarily as I begin a static. If I can reach maximum oxygen saturation by normal breathing (thus keeping my heart rate ~50bpm), shouldn't this help my static? Or does the deep breathing confer benefits (increased oxygen saturation?) that make the spike in heart rate before a static due to deep breathing worthwhile?
• Is it even worthwhile to perform deep breathing throughout an apnea preparation phase? (my reasoning for which was to purge the dead air from my lower lungs as much as possible) Or is it sufficient to breathe normally for a few minutes to get my heartrate as low as possible, then perform a few deep breaths (say, 3?) right before the apnea. Would this maximize my oxygen saturation as much as several minutes of deep breathing?
• I remember a thread I read about many users' experiences with oximeters. Many individuals pointed out their observations of their reducing oxygen saturation during a breath-hold, but did anyone make observations of how long in the recovery phase after a breath-hold their oxygen saturation returned back to normal? I have heard that the body returns to normal saturation level quickly, while I have also heard that it takes "approximately 5 minutes". It seems to me that it would be favorable to take the soonest possible opportunity in the recovery phase to enter the next breath-hold in a succession of breath-holds to reach a max static, in order to take advantage of the exaggerated dip in heart rate that happens within minutes after a long breath-hold (e.g., I've observed my heart rate to dip to 41bpm after a long breath-hold, despite that my resting HR is ~48bpm). Just wondering if someone has a more accurate estimate of the minimum recovery time to reach normal saturation level? (I realize that a longer recovery time would be necessary after a longer breath-hold, but I have a hunch that the range in duration of it is surprisingly minimal).

Thanks.

[trux]

Regardless if we speak about static or dynamic apnea, hyperventilation (at that's exactly what you do according your description), is in freediving generally considered as very dangerous and even counterproductive. Saturation breathing does not necessarily have to be deep - you will find different descriptions and approaches if you look through the forum, but generally it is a rather fast inhalation (i.e. 4 counts), short breath hold (i.e. 3 counts), and then looong slow exhalation (count 12-15). It is the slow exhale that calms down the heart and can even induce bradycardia.

Deep breathing will not help to oxygenate your blood, it only lowers the CO2 level in the lungs and in your blood, which is very dangerous for several reasons:

• higher probability of LMC or blackout due to delayed urge to breath
• low acidity hence high O2 binding of hemoglobin, with consequent reduced oxygenation of brain
• carotid constriction and hence brain hypoxia at the beginning of the apnea with the possibility of blackout in the first phase of apnea
• increased heart rate
• higher O2 consumption
• delaying or suppressing of the diving reflex

Read more information for example in the thread http://forums.deeperblue.net/static-...-good-bad.html

The revolutionary method of Seb Murat even teaches to ventilate less than normally (and to dive on empty lungs), to kick in the diving reflex as fast as possible - just like seals do. The performances they achieve with this method are amazing. Read more about it for example in the article at Fridykning.se

[Ol Dirty Diver]

I actually don't think I'm hyperventilating; I've definitely been made aware of its pitfalls from the numerous posts criticizing it. I suppose 'deep breathing' is ambiguous, and can mean many types of breathing. To be more specific, my 'deep breathing' entails very technique-focused, slow breathing. I begin by pushing my belly out to fill the lower lungs, then fill my upper lungs, which takes ~6 sec. I don't hold my breath at all at peak inspiration, instead progressing right into my exhale. I focus on making my exhale as slow as possible, at least twice as long as the inhalation, with a finish that involves drawing my diaphragm/belly in as much as possible.

If that qualifies as hyperventilation, then I've been doing it inadvertently all this time even though I've been trying to avoid it! I actually realized my so-called "belly-breathing" method on my own, when I started running and learned that it was a way to alleviate and avoid my frequent stomach cramps (the mechanism of which was through relaxing my diaphragm muscle, which was contracted too much, thereby producing the cramp). Through some reading I recognized how similar my form of breathing sounded to proper deep breathing in preparation for apnea. I think I also gathered some support for it through hearing the mention of making the exhalation at least twice as long as the inhalation during the David Blaine TV special (I think Kirk Krack discussed it).

Just wanted to offer that clarification in case you were dismissing my inquiry due to believing that I was hyperventilating (correct me if I am still wrong after hearing my explanation). Does my form of deep breathing actually differ from what experienced apneists do? I feel like I drastically improved my apnea potential when I began implementing it. Anyway, I do notice that my heart rate can drop a few beats during the long slow exhalation of a deep breath (whereas it rises during the inhalation), but my avg. heart rate during the deep breathing is nevertheless ~20 beats higher than when I breathe normally. One of my inquiries posed the question of whether this seemingly necessary rise in heart rate associated with deep breathing was unfavorable enough that deep breathing should be avoided except right before the breath-hold. I don't know why, but for some reason I've always done deep breathing throughout my apnea preparation phase, and now I'm questioning whether this is appropriate or detrimental.

Thanks for your help.

[trux]

Technically taken, it is still hyperventilation, as far as I can tell. Maybe it is not extreme, but it is hyperventilation, and very likely it leads to decreased CO2 level. If you can measure the tidal volume of your breath (or estimating it by % of your measured pulmonary vital volume), and count the number of breaths per minute, you can calculate the O2 saturation and CO2 dropping with the online calculator at AltitudePhysiology.org.

[wes]

Kurt,

I have been doing many static tables with HRM under pretty controlled conditions and based on that here is my take on your breatheup. I think Trux is right, it is hyperventillating as it is breathing more than you normally would so lowering your CO2 (which has pluses and minuses for static as mentioned in the thread, everyone agrees you don't want to do it alot anyway). As to how it serves you, I do think that getting a very full exchange of fresh air is beneficial just before the last inhale in a static. The problem is that if you breathe very fully with stomach, chest and upper rib cage then you use lots of muscles and raise your heart rate. The thing that I do after wrestling with these issues is to do a type of breathing that is very slow like Trux describes though that uses only my lower belly muscles and on the last 2-3 breaths before the last inhale I do "purge" breathes with this technique though only engaging the very lowest belly muscles while keeping the middle and lower chest flat or at minimal volume. This lower volume of the middle and lower chest allows the air sucked into the lungs by the belly breathing to mix very deeply into the lungs and then full belly exhale and do this 2-3 times to purge and get all fresh air for final inhale. This would be kind of like hyperventillating though by not using the middle or upper chest muscles you are not taking a full breath, maybe only 40% or 50% of a breath so has less affect on purging C02. So end result is fresh air with a lower increase of heart rate (for me anyway). Don't know if this is true for everyone or is ultimate answer though something to play with - Cheers Wes

[trux]

Yes, I agree that some level of hyperventilation or a purge breath may be needed to accelerate the gas exchange, but in contrary I think it is better after the previous performance to quickly blow away hypoxia and toxins including excess CO2. I used to do purge breathes just before the apnea, and almost all freedivers I know do it too, but the more I read about diving physiology, the more I see that it is actually counterproductive.

The volume of oxygen you gain with the last purge of hyperventilation is not big, but the level of CO2 may rapidly drop, with the consequence of carotid arteries contraction, higher blood acidity and the resulting lower oxygenation of brain, tachycardia, and especially considerable delaying or partial or complete suppression of the diving reflex.

Just read some posts of Sebastien Murat or Will Trubridge who advertise FRC and slightly hypercapnic diving. I think also Will Winram applies these methods, though am not sure now. Or read the article about Murat's school of diving at the link I posted in my previous message.

[wes]

Trux,

I agree also with what you are stating on the benefits of having CO2 for a static apnea or a FRC dive. Seems like the "crazy tables" that were referred to at 2007 Egypt were a way to keep high levels of C02 while still keeping 02 levels up by gulping just a bit of air at a time while starting with a negative hold.

To summarize my point above, it is that if you do want or feel you need to do a purge breath before the last inhale then you don't need to take a huge full inhale and then exhale, you can simply take a deep belly inhale and full belly exhale while keeping the chest flat or deflated and this gives good gas exchange with less work and lower heart rate then full inhale and full exhale. Cheers Wes

[Ol Dirty Diver]

I just want to thank you guys for your replies. The way I see it, a personal experiment is in order to try these different ideas out. Because of my science background I usually don't just accept ideas on faith, but instead plan to test them using experiment and observation in order to validate them. The good thing is that now I know there was something very unfavorable about my preparation due to your feedback (I'm glad I was keen enough to question it; I really thought I had a good method down). The possibility of drastically improving my preparation phase by breathing much differently makes me optimistic that I will reach much better performances now. The original motivation for my inquiry is that I hit a 5:46 (dry) static a few weeks ago, in only my second attempt at a static, so I thought I'd surely surpass 6:00 in the next attempt, but a few attempts have gone in which I couldn't do any better. My contractions have always been hitting me as early as before 2:00 (whereas on my best time they didn't start until ~3:00), so I knew I was doing something wrong.

Trux, I read the Murat article you mentioned. Very interesting stuff. My only problem with trying that is that I am so cold in the water already, and it doesn't seem to help me at all! Throughout my freediving thus far (in the arguably balmy waters of Hawai'i), I have been cold to some degree (usually to the point of shivering), in spite of upgrading wetsuits multiple times. A 3mm two-piece still doesn't do the job, so I've gone so far as to order a 5mm now (which I had to order because they don't even sell 5mm in Hawai'i!). My problem most likely stems from my relatively low body fat percentage, 5.1%. In addition to my bottom time becoming very markedly reduced, I have routinely dealt with a very alarming condition that comes on once I get cold. It is similar in description to lung squeeze (my lungs begin to feel heavy, my breathing is impaired, eventually I can hear "rales" and feel the fluid building up in my lungs), except that it doesn't necessarily come on with diving to significant depth. I experienced it bad once while diving only to 12m, and another time in only 5m of water. The only thing it seems closely associated with is my becoming cold early in the dive. Perhaps I did experience a lung squeeze early on (first time was that 12m dive, described here), and now I am very susceptible to it, but the weird thing is that it doesn't happen every time. I have had some dives to 35m where it didn't come on. So it's been very hard to understand and a nuisance to deal with.

I know this is getting off topic, but I always wanted to present my "leaky lungs" case. It might just sound like lung squeeze to you, and you might just reckon that I have been a fool to keep diving with it, but it seems a bit different from lung squeeze and not as severe...I just accept it and deal with it carefully. To me it doesn't sound like the cases of lung squeeze I read since mine can come on with very shallow diving (I remember reading that lung squeeze was defined by diving past your residual volume), and since it happens sporadically (why would it happen one week in 15m diving, then not happen the next week in 35m diving?). The only clear association is that I am cold when it happens. I was once suggested to inquire with the Divers Alert Network (DAN) about it, and they quickly replied back that it was "immersion pulmonary edema". Pulmonary edema doesn't necessarily sound distinct from lung squeeze, but may be a component of it. Anyway, I don't recall anyone pointing out that lung squeeze was associated with being cold, whereas everything I've read about immersion pulmonary edema mentions that while it is not well understood, it is closely associated with the subject being cold when underwater. It is my hope that when I am toasty in my new 5mm suit, I'll never have to deal with it again.

Sorry for wandering off into this topic, but in my desperation to seek answers about it I thought I'd go ahead and mention it. I could move this message into a more appropriate forum.

Thanks.

[adolphin]

Originally Posted by trux

Technically taken, it is still hyperventilation, as far as I can tell. Maybe it is not extreme, but it is hyperventilation, and very likely it leads to decreased CO2 level. If you can measure the tidal volume of your breath (or estimating it by % of your measured pulmonary vital volume), and count the number of breaths per minute, you can calculate the O2 saturation and CO2 dropping with the online calculator at AltitudePhysiology.org.

trux, hi there .. .. do you have an idea what is the average tidal volume for 95% full lungs ?! .. I know the figuers vary according to total volume of each individual's lung, but the calculator doesn't accept more than 5 liters, anything beyond will be considered as beyond human nature ! .. is that true? .. anyway, if it was 5 liters at 0 m alt then it states that 2 breaths will still be ok (not hyperventilation) .. now I can do two very deep breaths each minute .. do you think it wont be considered hyper ? according to what I understood from the different references, it is hyper as long as it is TOO DEEP .. any idea?

[trux]

Adolphin, average tidal volume at an adult is around 0.5 liter. Whether you hyperventilate or not depends on two factors - the frequency of your breath, and the tidal volume. You may be breathing shallow but fast and still may be hyperventilating.

[adolphin]

trux .. I know the normal tidal volume of an average person would be 0.5 liter or so, the calculator is suggesting 0.65 liters at a respiratory rate of 13 per minute. This is not my question, 0.5 liters is only a fraction of the maximum tidal volume that a person can achive by filling the lungs fully and emptying it to the max as well (residual). So my question is if an average person wants to breath up to 95% of maximum lung volume what would be the tidal volume of such inhale ? would it reach 5 liters or so? or is it much more, coz I assumed that the lungs capacity of an average guy should be around 7 liters no?

[trux]

Most sources show average Vital Lung Capacity (that's the term for the volume you speak about) at adult males slightly above 4 liters (~4.2 - 4.3 liter), other sources show up to 4.8l, but of course it depends very much on each individual so it can be anywhere between 3l (or possibly even less) to 10l (or possibly even more at some individuals). AFAIK, there are couple of athlets having the vital capacity 14 liters and possibly even more with packing.

EDIT: This may be a good start if you want to know more about this topic:
Lung volumes - Wikipedia, the free encyclopedia

[adolphin]

Great, then back to my earlier question please:

anyway, if it was 5 liters at 0 m alt then it states (in the calculator)that 2 breaths will still be ok (not hyperventilation) .. now I can do two very deep breaths each minute .. do you think it wont be considered hyper ? according to what I understood from the different references, it is hyper as long as it is TOO DEEP .. any idea?

and thanks for the wiki link, I already read it before .. thanks bud ..

[trux]

I'd rather suggest to stop bothering with it and stressing with some calculations that will never be exact anyway. Breath up just normally, without any mind control or forcing. Rather than breathing deeply, concentrate on the complete relaxation and it will have much better effect. You can breathe somehow deeper (without forcing), but try keeping the inhalation short (inhalation stimulates tachycardia - increase of the heart rate), hold for 3-5 secs, and then expire very very slowly (expiration stimulates bradycardia - slowing down the HR). Do not try to control the breathing by your ribcage or diaphragm muscles (it adds tension and consumes oxygen), but rather by your lips. Make the expiration about 5 or more times longer that the inhalation, but do not stress about trying to measure it exactly. Simply concentrate just on your relaxation,

[adolphin]

ok trux .. this is rather a practical answer (not scientific) .. and surely not the answer for my question .. .. but it's a sum up for what a proper preperation ventilating should be ..
I usually do all what you said, except ofcourse the deep breathing problem, which I shall reduce it now so it will be moderate .. thanks bud ..