simulating altitude

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Dave Dinnell

 
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by Dave Dinnell » Tue Feb 02, 2010 8:07 pm

Ze wrote:hyperventilate


Or run bleacher stairs dressed like this guy...Image :lol:

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Sierra Ledge Rat

 
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by Sierra Ledge Rat » Tue Feb 02, 2010 9:26 pm

The purpose of post is to explore in detail the usefulness of altitude simulator devices such as the Altipower Pro based on existing scientific research.

I will start by stating that the theory behind the Altipower Pro is completely flawed, and I would like to provide you with an analogy before I prove my point.

Let’s pretend that I am marketing an exercise device. Here is my sales pitch:

“Get cardiovascularly fit in half the time!

“Running has been scientifically proven to increase aerobic performance and strength!

“With our new Leg Cycle machine, you can sit and watch TV while your legs are cycled just like you are running!

“Since our Leg Cycle machine moves your legs twice as fast as when running, you can get fit I half the time!”

“Watch TV for 30 minutes while using the Leg Cycle machine, and you’ll get the benefits of running for an hour without leaving your couch!”


Okay, so that’s a little silly, we all recognize this. But the claims of the Altipower Pro are just as silly. They are taking sound science and stretching it past the point of proven benefit, and making “if-then” presumptions that are simply not true.

The most sound intermittent hypoxic training methods are the live high-train low (LH+TL) methods, where athletes live at altitudes of 2,000 to 2,500 meters for 8 to 18 hours a day for 4 or more weeks at a time, but train and low altitudes (sea level). More properly, this should be referred to as intermittent hypobaric training, not intermittent hypoxic training.

Although both hypobaric and hypoxic training use a lowered partial pressure of oxygen (pO2), there is a physiological difference between lowering the barometric pressure and lowering the fraction of inspired oxygen to achieve a lower pO2. The difference is slight, and is why intermittent hypoxic training is substituted for what you really want -- intermittent hypobaric training. Kinda like substituting a stair climber for actually running on mountain trails.

Intermittent hypoxic training (IHT) is based on the unproven assumption that, in terms of altitude acclimatization, you can breathe a lowered fraction of inspired oxygen at rest for only 1.5 to 2.0 hours a day to reap the same benefits as several weeks of LH+TL.

It true that intermittent hypoxic training (IHT) has some scientifically-demonstrated benefit – but not universally so. For instance, in one study of older men, IHT demonstrated no benefit in those men who exercised regularly. But there was statistically significant benefit in sedentary men.

As an alternative to IHT, some have also suggested training under hypoxia to speed acclimatization. However, studies have shown that both training at altitude and training under hypoxia leads reduced speeds, reduced power output, and reduced oxygen flux.

Bottom line: breathing through a $1,000 gadget, or any other gadget, has never been scientifically proven to accelerate high-altitude acclimatization or improve performance at altitude.

But if you believe in the Altipower Pro, let me sell you my Leg Cycle Machine, too.

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1vertical1

 
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by 1vertical1 » Wed Feb 03, 2010 11:51 am

[quote="Sierra Ledge Rat"]The purpose of post is to explore in detail the usefulness of altitude simulator devices such as the Altipower Pro based on existing scientific research.

Thanks for all your research, but the purpose of this thread was to explore simulating altitude without an altitude simulator. Sorry if I did not make that clear. I was looking for some way I could add to my training that would help to prepare for altitude by simulating acclimatization.

Thanks again

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Ze

 
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by Ze » Wed Feb 03, 2010 3:36 pm

here is somethingthat I had written up previously based on doing a little research on altitude sickness. just put it on my new crappy blog.

the gist of my speculation comes near the end
This seems somewhat odd but basically this is what short term acclimatization is...getting used to hyperventilating. You can get used to hyperventilating at altitude (multi-day excursions with gradual increases in altitude) or consciously force yourself to get used to it. You won't have the hypoxia to stimulate the hyperventilation, so you'd have to do it yourself.

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1vertical1

 
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by 1vertical1 » Wed Feb 03, 2010 3:59 pm

I am already overtrained and have a fantastic vo2 max ( 78 ) and I have use diamox in the past with good results, but I get between 16000 and 17000ft and all goes to crap for me. I guess all I can do is take more time...shit.

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RayMondo

 
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by RayMondo » Wed Feb 03, 2010 4:20 pm

Apart from all the known technicalities, there remains the unanswered as to why some people who've never been high don't get problems when the well trained do.

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1vertical1

 
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by 1vertical1 » Wed Feb 03, 2010 4:59 pm

That is what I was thinking, but no harm in trying.

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1vertical1

 
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by 1vertical1 » Wed Feb 03, 2010 9:38 pm

Thanks

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Ze

 
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by Ze » Wed Feb 03, 2010 9:57 pm

Generally (at sea level), the heart is the limiting factor in delivery of oxygen to the muscles. The muscles are ready to use more oxygen, but the heart simply cannot pump any faster to get more oxygen to the muscles. (Blood is 100% saturated with oxygen)

At altitude, the reduce pressure of oxygen in the air slows down the rate of transfer into the blood stream. Now, the % saturation is less than 100%. It has nothing to do with fitness; in fact, sometimes being in great shape is actually worse, because the proper workload to not ascend to quickly may actually be mush less than what the person is used to.

You have to improve the ability to transfer oxygen from lungs to blood. And people do that - by hyperventilating. The problem with hyperventilation is the side effects (like dizziness).

Many high-altitude dwellers have chronic hyperventilation.

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Luciano136

 
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by Luciano136 » Wed Feb 03, 2010 10:08 pm

I dunno. The only thing you can do is go on altitude on a very regular basis. It seems to help me a lot; this is not based on any scientific fact but just personal experience. Somehow my body adjusts much faster with regular altitude exposure.

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Grampahawk

 
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by Grampahawk » Wed Feb 03, 2010 10:27 pm

RayMondo wrote:Apart from all the known technicalities, there remains the unanswered as to why some people who've never been high don't get problems when the well trained do.
Maybe not having smoked so much dope when in college kept their lungs cleaner than those who got high :oops:

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RayMondo

 
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by RayMondo » Wed Feb 03, 2010 11:35 pm

It's likely there is a genetic link to altitude acclimatisation. Like the newly discovered longevity gene - the extent to which our telomeres can be sustained throughout a lifetime of cell regeneration. Interesting that there is now a drug to support it. TA65 $25,000 for a years supply. Heck, one could do a whole bunch of climbing instead. Natural telomerase is produced by the reproductive organs. So, I'll say no more :)

<a href=http://http://longevity.about.com/od/researchandmedicine/p/telomeres.htm>Telomeres</a>

<a href=http://http://websites.afar.org/site/PageServer?pagename=IA_b_tel_5_role>US Federation for Ageing Research</a>

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Outside

 
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by Outside » Thu Feb 04, 2010 12:07 am

I'd have to agree with FortMental. Denali is a dangerous place to have a problem and even more-so if you EXPECT to have one. Further, aside from jeopardizing your own well being, you are exposing your climbing partners to unnecessary risk as they attempt to deal with your condition as it presents itself in brutal conditions. Not to mention the potential of screwing them all out of a shot at the summit. Perhaps $$ is not a problem for you but a voluntary LAMA ride out of the 14 camp will run about $1000.00. To get a free ride you will likely be borderline comatose. If you're going with a guided trip, tell them now about your altitude experience. You seemed to proven to yourself that altitude is not your bag. Denali is no place to test your new fitness regimen. People die there. The only thing predictable is the unpredictability. So don't do it. There are hundreds of other pursuits that will be better suited for you.
If you read FortMental's classic Denali TR, however, you may find the secret to many climbers success above 14 camp, the now famous J&D. (Jaegermeister/Diamox cocktail). Just joking-I doubt that it really works.

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Sierra Ledge Rat

 
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by Sierra Ledge Rat » Thu Feb 04, 2010 3:12 am

Ze wrote:You have to improve the ability to transfer oxygen from lungs to blood. And people do that - by hyperventilating. The problem with hyperventilation is the side effects (like dizziness).


Hyperventilation has absolutely nothing to do with the transfer oxygen from lungs to blood.

Mathematically, we can calculate the aveolar-to-arterial oxygen gradient (A-a gradient):

A-a gradient = (FiO2*(PB-pH2O) - paCO2/R) - paO2

where:

FiO2 = fraction of inspired air (21%)
PB= ambient barometric pressure
pH2O=partial pressure of moisture
paCO2=arterial partial pressure of carbon dioxide
R=ratio of inspired CO2/expired O2
paO2=arterial partial pressure of oxygen

As you can see, variables for respiratory rate or minute volume are no where to be found in the equations.

We can also calculate other measures of oxygen transfer such as oxygen delivery, alveolar diffusion capacity, etc., and none of those equations contain variables for respiratory rate or minute volume.

And don't even try to argue that R is dependent on minute volume. Inspired CO2 is a constant and expired O2 is a function of metabolism. If you want to do the math, calculations of O2 consumption and expired O2 are also not dependent on respiratory rate or minute volume.

You could make an argument that paCO2 is a function of minute ventilation, but paCO2 is small and changes very little from pvCO2 to paCO2 (in relation to the magnitude of paO2), and the factor of paCO2/R is so small as to have a negligible effect on the A-a gradient. Therefore, it would difficult to argue that the A-a gradient depends to any significant degree on the minute ventilation.

Furthermore, at altitude it is the barometric pressure that determines arterial oxygen saturation, not the respiratory rate. The hemoglobin dissociation curve is entirely independent of respiratory rate or minute volume. Again, avleolar diffusing capacity is also independent of respiratory rate or minute volume.

Clear?

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Autoxfil

 
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by Autoxfil » Thu Feb 04, 2010 1:54 pm

SLR - thanks for the math. I'm still a bit confused, though:

The way I've been taught, forced hyperventilation is a good technique because one of the main issues at altitude is that your body's auto-regulating systems break down. Specifcally, the CO2 transfers from the blood to the atmosphere easily, but O2 doesn't make it into the blood as well. Since the body relies on CO2 content in the blood for regulating breathing, you don't breathe as heavily as you need to in order to get enough O2.

This makes intuitive sense - your equations seem to imply that the aveoli are bathed in the atmosphere. But as a breath is held, doesn't FiO2 drop as O2 migrates to the blood?

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