SWB: Reducing the Risk

[tylerz]

Actually hyperventilation is defined to emphasize that there is more ventilation occuring whether through increases in frequency, depth, or both of ventilations. Essentially for our purposes, whatever reduces CO2 to levels below tidal breathing. Therefore, even at 2.5 breaths per minute one can be hyperventilating depending on the manner it is achieved and personal circumstances. Remember that each of us has a different ability to ventilate CO2, so "all 10 quick breaths are not created equally" One really has to learn about the effect of a breathing style on their body specifically. I believe to produce the safest and most accurate results we need to begin focusing on how to teach people to detect and determine what works for their body, as opposed to the tradition of passing on arbitrary rules.

[shoutatthesky]

I agree. There is no one standard breathing style right for everyone. It sounds to me as though Amihov is advocating quick shallow breaths and it is that old school type thinking I am questioning. I am just adding some words of caution.
I think that those of us aiming to exceed current performance levels are going to have to be educating ourselves in the use of such devices as oximeters, spirometers, expiratory gas analysers, etc. to arrive at some much more personalized parameters regarding breath ups, warmups, and the many other variables that exist. In many ways the term 'hyperventilation' is too general a discription to be of much use in todays freediving environment.
In reality, to say without doubt that anyone is breathing up correctly, there must be some personal parameters established for that individual through the use of these technologies.

[trux]

Originally Posted by efattah

Trux theorized that the spleen only 'helps' in subsequent breath-holds. In fact I would say it is the opposite.

During the first apnea, the spleen will release its oxygenated red blood cells into the blood stream during the late stages of apnea, when vasoconstriction has already occurred. So these precious red cells will have their O2 used in the most constructive way.

Sorry, Eric, but this is misinterpreted. I only disputed the claim that the splenic contractions help with pre-stocking of the oxygen at the first apnea(s). It is clear that the additional red blood cells help with more efficient oxygenation, transferring the remaining oxygen from lungs, but:

1. Unlike at seals, at humans, the spleen starts releasing hematocrit with big hysteresis quite slowly, so that it is usually measurable only after a series of breath-holds and
2. I suppose the hemoglobin stored in spleen is not fully charged (note: I did not find any confirmation or denial of this claim in literature, and am not sure about it, but do not really believe it is saturated with oxygen when not used and stored in the spleen). Hence although its release greatly helps with the transport, it does not help with the pre-stocking, until you can charge it by breathing from the atmosphere (I do not consider charging it from the lungs during apnea for pre-stocking, because it just depletes the available oxygen that could be used without the extra hemoglobin too, just little bit slower and less efficiently)

Hence, on my mind, at humans, the splenic contraction really does not really help at the very first breath-holds. And unfortunately, its help, even at full splenic contraction, is not that great as one would desire.

[amihov]

Well about the hyperventilation. I have to say that it is a condition of the human body and it can be felt. How many breath ups we are doing has very little to do whit that stage. It is more like a feeling .When you reache that stage you will feel high. You will feel like your head is spinning. To avoid this condition you have to stop what you are doing. What i do is when i feel the fist symptoms of this condition i just stop. And next time when i am getting ready for a dive i just do less breath ups. I tray all of this in a apnea walk first . Then i go to the pool. And after i have found that it works for me in a apnea walk and in a pool session i use it in the ocean. Right or wrong this is how i do it . I am sharing this because i want to hear other people's opinion .

[tylerz]

Hyperventilation is an action, not a state of the human body. As a consequence of hyperventilating you may reach a perceptible condition of hypocapnea. However, in terms of diving, a risky level of hypocapnea can definitely occur without any sensation prior to the dive. I do not think there are any accurate practical scientific methods to determine for an individual what degree of ventilation is the safest, therefore currently it can only be found by trial and error (max attempts with consistent comparison of differing preparation where one method consistently ends in LMC or blackout). I was lucky to be able to witness this sensitivity in preparation recently during Will's training for his world record attempt.

[shoutatthesky]

Tyler, in your training with Will how many of these incidents of LMC or blackout did you witness?

[tylerz]

A handful.