Get high and get on down: a response

[Alun]

one thing to bear in mind is that Mark could have breathed normal air during those IHT sessions and still have done 7mins at the end of it! when i used to do static years ago i beat my PB by about 15-20secs on a few occassions - this was when it was around 7mins. so i would be cautious about attributing Mark's result solely to the IHT, although i'm sure it was a contributing factor to some degree.

i don't think doing negative statics is a good idea, because i think the negative pressure in your lungs is pretty severe due to the recoil of the ribcage when you relax your intercostals. (ok if you continue to contract your intercostals and abs, but you're not relaxed!) i think passive exhale statics are much better for you...

[naiad]

Originally Posted by Alun

i don't think doing negative statics is a good idea, because i think the negative pressure in your lungs is pretty severe due to the recoil of the ribcage when you relax your intercostals. (ok if you continue to contract your intercostals and abs, but you're not relaxed!) i think passive exhale statics are much better for you...

Why is the negative pressure bad? Is it bad to have strong contractions with negative pressure?

Lucia

[Alun]

because if the pressure differential is big enough then alveolar capillaries will burst. contractions with negative pressure... yes, really bad!

[AltSaint]

Don

The graphs that Richard produced were samples from a 'bad' day at the beginning of the exercise, and a 'good' day toward the end. As with many experiments, there were lots of variations inbetween. Although the sessions were well-controlled, my lifestyle over the three week period continued as per normal. So I had days where I had drunk alcohol the night before, days where I had been stressed at work or not slept well the night before, and my diet would have varied to have made changes to my blood ph levels.

Richard was keen to keep my buffering above 80%, not so much for training reasons, but for concerns about damage to health. This was probably erring on the side of caution, as we know that many of us ( such as Eric F ) can tolerate much lower percentages without any perceived bad side-effects.

The main difference between breath-holding and IHT aspiration, is that IHT is constantly removing the CO2. With breath-holding, C02 builds up to the point where you have to breathe, or where you black out. With the former, this is a safety valve that IHT does not have. This is why it is important to keep higher buffering percentages. ( This is my understanding, although I am not an expert! ).

As part of the experiment, I also used a personal hypoxicator, and this is designed to not allow lowering of O2 percentages to dangerous levels ( I don't think I managed to get it below 12% ).

All of this isn't really answering the question about how you should adjust your training, but might give an insight into how variations occur, and the relevance of the buffering percentages used in these trials.

HTH
Mark

[AltSaint]

Alun

I agree with your comments about the PB - this could have entirely been 'the placebo effect'. The buffering graphs are a bit more evidential, even without seeing the full range. The overall trend was a definite increase in buffering ability.

Mark

[DrLindholm]

I read Donmoores observations on empty lung apnea and pulse oximeters.
The oximeter results you refer to is probably wrong, they sound very strange.

Pulse oximeters with the probe on the finger is not workning properly for apnea. First there is a delay so that the oxygen level that hits the brain will hit the finger oximeter 20 seconds later, i.e. you will have no warning from that oximeter to prevent a blackout. Second the diving response cause vasoconstriction so that the blood will not circulate properly in the finger which suggests that the oxygen readings in the fingers is not representative of what your brain gets. If you want to use an oximeter during apnea, you need to use an ear lobe probe. I think that if you did 2 minutes statics on empty lungs you were probably on the edge of an LMC/BO with a true saturation of 50-60%.

[donmoore]

Dr. Lindholm,

So glad to hear your opinions. I love to read your papers as you have probably done more research than anyone else on apnea.

if you did 2 minutes statics on empty lungs you were probably on the edge of an LMC/BO with a true saturation of 50-60%

That’s a little scary. If it weren’t for the possible damage Alum referred to, I would push it farther to see if I was in fact on the edge of LMC/BO. But from the pain associated with the contracts in the first few holds, I am afraid Alum is right that damage could be done.

The speed in which the SaO2% reading was falling after about 93% was incredible, like 1% every 1 to 3 seconds, so any time delay from vasoconstriction in the finger could have caused a large difference in true SaO2.

I would love to have an oximeter with an ear lope attachment, but the model I have is an all-in-one finger unit so adding a different probe is not possible. I better start searching E-Bay again. With normal full lung dry statics I have been down to 60% SaO2% on the finger unit 3 times and 1 resulted in a LMC.

Is the reason why Richard from The Altitude Centre was able to use a finger probe on Mark is because with IHT CO2 accumulations is less and does not cause as much vasoconstriction? I was under the opinion that a finger probe was pretty accurate down to 70% SaO2 as most of the manufactures say accuracy is +-2% from 70 – 100%. But from your message it sounds like that is with breathing and expelling CO2 and not with apnea.

Mark,
Thanks for you further explanation. You got me confused now. What is the difference between IHT and a personal hypoxicator?
don

[AltSaint]

Don

Where I was referring to IHT, I really meant the treatment I underwent at The Altitude Centre. This was on a ventilator connected to a mixing unit and PC. The personal hypoxicator is a lightweight portable unit, with a rebreather and scrubber. About the size of a football.

I think Dr. Lindholm makes a good point about pulse oximeters and the diving reflex. I even wondered during the experiments if this effect was happening, as you can see on my charts that the dips are fairly rapid. Also, I experienced a frequent need to urinate throughout treatment, which suggests that blood was diverted into my core and increasing filtration through the kidneys.

Mark

[DrLindholm]

The finger probe will work very well during hypoxic breathing (IHT) because you are breathing! there will still be a delay but a delay of 20 seconds doesnt matter much when you are talking about minutes. The problem with the vasoconstricition and fingerprobes during apnea has to do with apnea and the diving response, and the delay may pose problem during exhale breath-holds because saturation changes very fast. Most pulse oximeters are calibrated and accurate down to 70-80%.

Unfortunately the manufacturers of this medical equipment does not care to much about altitude training and apnea training methods, they only want something to work in the clinical setting. Well, most doctors and nurses I have met start to get nervous when saturation drops below 90% (wich usually indicate a serious problem in a patient) so why make something that reads accurately below 90%.

[efattah]

I have an earlobe sensor for one of my oximeters (Ohmeda 3900P), and I can say that if my perfusion reading is high, then the ear lobe sensor gives almost identical results as the finger sensor, except that the finger sensor has a 25-30 second response time, while the ear lobe sensor has a 10-12 second response time. The perfusion reading is an indicator of how much blood is flowing into your fingers. Most newer oximeters have perfusion indicators.

On the other hand, if my hands are cold and/or poorly perfused, then the earlobe sensor gives more accurate results. The problem with the earlobe sensor is that it also can suffer from a low quality signal due to bad blood flow in the ear, which is why you are supposed to rub the earlobe with isopropyl alcohol beforehand. That seems to help only marginally.

[ADR]

Day 4 today of my IHT sessions on the homemade Hypoxicator. I've built an oxygen analyser as well now as I was getting annoyed with referring to conversion charts with the millivolt meter. With my newly aquired 3900P oximeter measuring SaO2 and the analyser measuring FO2 I'm having a whole lot of fun training "hard" in front of the TV (Faulty Towers this morning). With a rebreather style unit that has no bottom limit I have to keep an eye on things to stay at 10% FO2 which currently relates to about 81% SaO2. The unit allows me to maintain anything from 0-21% which is remarkable for 1/2 a days work in the workshop!

I'm not entirely convinced that I'll see any improvement in my apnea limits but it is fun nevertheless.

Andy

[donmoore]

I remember Eric Fattah saying how the blood in an artery maintains its O2% regardless how far along its path it is from the heart. The reason, if I remember correctly, is O2 is not draw from the blood until the blood exits the arteries into the capillaries. In the capillaries 02 is draw out and CO2 is put in. The blood exits the capillaries into the veins. Blood pressure and volume maybe lower in an artery the further away from the heart it is, because it has been diverted in so many places, but the blood that makes it to a particular point, has the same SaO2% as it did when it first left the heart.

So if there is a large lag time with a finger probe then would a more accurate reading of the lowest SaO2% obtained be after the hold ended? The lowest SaO2% at the main artery leaving the heart will eventually make its way to finger, even if its 25 seconds after the breathold ceased, won’t it? Withstanding machine problems from too low of perfusion, algorithms, reading frequencies, etc. the pulse/oximeter should eventually read the true SaO2% obtained at the end of the breathold and it should approximate the lowest reading obtained 20+ seconds after the hold ceased, shouldn’t it?
don

[tylerz]

***DISCLAIMER***
I don't recommend you trying this. This is for informational purposes, and without consideration of dangers and a safe environment to practice, this can lead to serious injury.
***

I managed to work out a sequence that one can do without any equipment which should simulate the IHT conditions as described in the article, as it did for me while exercising and analyzing with a pulse oximeter. Much less precision towards maintaining a specific SaO2 unless you have an oximeter on hand, but the results due to this inaccuracy are most likely to induce a greater adaptation.

This was created because my father is going to hike to base camp at Everest and he was looking for something to help with acclimatization. The values are tailored for him, having no freediving related adaptations currently, but after the steps I will put the variables I used to reach the IHT equivalent.

1. begin exercise until relaxed, continuing to exercise for the rest of the steps.
2. hyperventilate (quick inhales and exhales; inhaling 3/4 amount of a normal breath; 2 inhales per second).
3. exhale fully.
4. hold your breath.
5. when it begins to feel a little uncomfortable, repeat from step 2, but this time on step 2 only perform 3-6 hyperventilations.
6. continue the cycle for 5 min of exercise.
7. continue exercising normally for 5 min.
8. repeat from step 2.
9. continue full cycle 3 times in total.

Notes (remember these are written to a non-freediver):

Step #2: Every person is different when it comes to hyperventilating. We have different abilities to remove CO2 and this ability improves with practice. So, I think you will probably need to start with 20 hyperventilations on the first cycle and on every cycle after that, 6. The less the better. Also, hyperventilating assists at making your body more suceptible to fainting, therefore you need to closely listen to the sensations of your body for over-doing it. The first cycle requires more hyperventilating than the rest of the cycles to allow you to hold your breath longer on the first hold until your oxygen levels have depleted to a level that you intend to maintain throughout the exercise. (note: for myself I did about 15 hyperventilations for the first instance, and 3-5 for each cycle after that)

If you find you are becomming dizzier with each cycle after holding your breath, then perform less hyperventilation and this will induce a shorter breath hold, if you cycle when the same level of discomfort occurs.

Step #3: Remember we are trying to maintain as little time as possible with oxygen in the lungs, therefore perform these exhalations and inhalations with focus on haste.

Step #4: Holding your breath, especially on exhale is a little disconcerting and awkward. Just relax and don't push anything. There is no success or failure here, so don't worry about a thing. Don't struggle too much and don't give up. Just find the balance. You will probably find you can hold your breath while exercising for only 8-15 seconds. IMPORTANT: It does not really matter how long you hold your breath for, instead all we are interested in, is maintaining a lower level of oxygen in the blood. You will need to experience a subtle discomfort at the end of each breath-hold, but not much more than that. (note: on the pulse oximeter my SaO2 level would drop to low 70s by the end of my breath hold and during the hyperventilations, would rise to high 70s/low 80s. I could have easily adjusted the range higher similar to the IHT)

Step #5 (same as Step #2 but modified): When finishing step #4 DO NOT take a large inhale, or breathe normally, or hold your breath. You must hyperventilate immediately otherwise the CO2 buildup will become intolerable and you will end up becoming replenished with oxygen to normal levels. You now don't hyperventilate as much as the first time, since you are not just trying to satisfy your body's need to stop the build-up of CO2 and maintain the level of O2. By hyperventilating quickly a few times, you can get rid of the nasty CO2 and only replenish a slight amount of O2.

PRECAUTIONS:

1. If you have any history or are unaware of blood pressure troubles, heart conditions, etc... your should consult your doctor regarding your trip and intentions, and therefore the same applies to this type of training. The adaptations can thicken your blood, put stress on your heart, increase blood pressue, etc... all of which under normal circumstances your body has other factors to balance out those adaptations, allowing the body to be healthy and generally even healthier than previously. However, maybe there are conditions where this training would be too sudden or stressful.

2. Easy does it! The steps are the model, but you must be aware that your current body condition may require easing into certain things. Instead of performing this for 5min the first few sessions, maybe only do 2-3min and 6 cycles instead. Maybe hyperventilate a little more at first (say 10 times on each cycle) and if you can perform the full exercise a few sessions, then lessen the amount of hyperventilating to the suggested 5-6 times.

3. Hyperventilating can seriously make you faint, so no sudden movements especially in the vertical direction while performing these exercises. Get to know your body and hyperventilating. Only do 6 times the first time you try hyperventilating and do it laying down or sitting safely in the MIDDLE of your bed. Get to know what it feels like. If safely laying down or sitting in the MIDDLE of your bed, keep increasing how many times you hyperventilate, to find when/if you start getting light headed. Under these same conditions practice some breath holding after hypervenitlating. Just until you are uncomfortable to get a sense of your body. If you determine that you feel light headed after 20 hyperventilations then start with 1/4 of the number of times and slowly increase to see when you start feeling a little light headed. After holding your breath while exercising, and suddenly breathing, you will most likely feel a sudden wave of light-headedness. Note how severe it is and back off on the length of the breath-hold as well as derease the hyperventilating. It should be ok to feel a subtle wave of light-headedness. Just be careful. I felt it every time as I was working this out.

4. This practice is considerably stressful on the body overall. Low-oxygen conditions allow the build up of free-radicals, of which I know little about other than anti-oxidants are essential and vitamins to maintain a healthy body under these types of stresses. Take extra vitamin C and eat lots of vegetables and fruits, preferrably organic. This is of utmost importance. You can become very ill if you allow your body to be stressed in this form without adjusting your diet to the new demands. As well the adaptations often have to do with generating haemoglobin, which requires iron, therefore a good source of iron or iron suppliments is important.

Interesting to note, is that the same effect could not be achieved while remaining motionless. But then we need the exercise and it probably induces more adaptation than at rest. Remaining motionless if I hyperventilated as little as possible to allow me to hold my breath longer, the oxygen requirements would be replenished even if I held my breath to very low levels. Since the metabolism is very low at rest, the returning veinous blood was not depleted significantly, therefore the blood could be replenished quite easily.

Thoughts? Questions? Corrections? Mud-slinging?

Cheers,

Tyler

[ADR]

Hi Tyler,

Can you tell me what your saturations looked like during this as I have been unable to come up with an approach that allows me to do 5mins on 5 mins off for 90mins and in the "on" maintain Sa02 between 70%-80%.....for us mere mortals it's just too draining/fatiguing for that length of time(single session) and over 15-20 consecutive days.

thanks

Andy

[ADR]

oops - I just reread it and noticed this is only a 30min session of three "on" phases of 5mins. 3 "on" phases is about my limit and doesn't compare to the 9 on my homebuilt unit. Additionally I'm almost through 20 consecutive days, which there is no way I could do using breath hold....this is not a mud slinging attempt as I wish there was a simpler way that worked for the majority of freedivers.

Andy