Mt. Whitney Portal Store & Hostel Forums General Mt. Whitney Portal Store Message Board sucking in air at altitude

A great explanation of the "oxygen still at 21%, vs lack of pressure" is in Kenneth Kamler's book Surviving the Extremes. He explains the physiological adaptation the body has to make in extreme conditions and high altitude is one of the chapters.

We do not suck air IN when we breath, we exhale, contracting intercostal and diaphram (and pelvic floor!) musculature, squeezing air out. When we release the contraction, the vacuum created (remember, "Nature abhors a vacuum") which is filled with the surrounding air, since the external air pressure is greater than the pressure in our lungs. In that sense, breathing IN is a passive operation, it's breating OUT that is active. Since the barometric pressure is so much less (I thing about 1/3 less at 14,000 ft), it takes twice as much vaccuum to such in the same amount of air as at sea level. The 21% ratio remains the same, it's just needs a bigger bag, if you will, to contain, since it's not compressed in the 1/2 the space.

Have I confused you enough now?

That being said, my best ascent of Whitney was about ten years ago when I was with a wedding party and sick with Epstein Barr. Since I was the officiating minister, I did not have an opt out. Because I knew I was sick, I was sweep on that trip, took my time, and paced myself according to my breath, inhaling AND exhaling out my nose. (Decades of yoga helped) I would add that this works great with the rest step.

I mention it because not only was it the best of several ascents I had made, I was in better shape and the least affected of the party of a dozen or so, even those who had successfully trekked in Nepal.

Since then I've decided that pacing is the ticket. I also believe that's why you see so many of us old farts chugging along just fine. Can't wait to do it again!

Hope that helps.

Kerry, It seems to be the other way around. Breathing in requires contraction of muscles. Breathing out (expiration) occurs when the muscles relax. [1] Only if you breathe out hard do muscles contract.

"During quiet breathing expiration is a passive process, relying on the elastic recoil of the lung and chest wall. When ventilation is increased, such as during exercise, expiration becomes active with contraction of the muscles of the abdominal wall and the internal intercostals." [2]

Bob

(You can click on the reference numbers [1] and [2] in the above text to go to the references.)

Unless you're trying to do some funky maneuvers, the volume of the lung at the end of normal exhalation is the functional residual capacity (FRC). This is the point where the forces between the chest wall wanting to expand and the lung wanting to collapse are balanced - which is why we use that point as the end point of normal breathing. The key is that normal breathing entails muscular work (diaphragm primarily, intercostals and accessory muscles to a lesser degree) to increase the chest cavity volume - thereby causing an inflation of the lungs via negative pressure. Exhalation during normal breathing is almost entirely passive. Sure, you can force air out faster, or exhale to a lower point than this resting point (FRC), which can happen during heavy exercise ... but not enough to the point where you can 'relax' at the end of exhalation and a significant sized breath will passively enter your lungs. Just try exhaling as you normally would and see if your lungs 'passively' expand to inhale your next breath ... just please don't wait too long before actually starting to breathe again! Hmmm ... I guess I just like Dalton's explaination with partial pressures better ...

And to address Dave G's question - purposely trying to inhale as deeply as possible to expand your lungs (above and beyond your normal breathing) is not typically going to help much when hiking. The main reason it could help is to help prevent atalectasis (small areas of collapsed lungs) - this is not a common occurrance in someone who is walking around, let alone hiking. There are a few reasons you might find it helpful to do so using abdominal muscles - psychologically helping you to focus, your chest wall may have a harder time expanding if you have a backpack chest strap on tightly, etc. But otherwise, it will not likely help you too much in combating hypoxemia. It is also more inefficient (in humans) than breathing with your diaphragm.

we all better get this right! normally, at rest or sedentary, the act of breathing only consumes a very small part of our workload and oxygen consumption. On Whitney it is a little more at rest compared to sea level, obviously more when ascending.

but by the time one is in the Greater Ranges, that proportion rises exponentially, even at rest. I can vouch for the remarkably increased amount of breathing required at 22,000. It isn't too bad at rest, but just getting out of the tent gets you short of breath. I don't think I tried to decide what was the better breathing technique as I forcefully increased both inspiration and expiration. As inspiration seemed more natural, I suppose the forced expiration seemed a more willful and conscious and necessary mechanism to help shorten the time between breaths. This is a subjective viewpoint, not a scientific comment on what is the proper way to appropriately hyperventilate. There were times when panting felt good, and other times when deeper breaths seemed right. The biggest thing I learned about breathing was to anticipate: if you see a rock, a ledge, a steeper grade, start extra breathing now, don't wait a minute or two for your body's slower sensors to finally trigger the alarm. Harvey

Amazing that breathing, which we all knew instinctively how to do at birth, could be such a controversial subject! <g>

Hmmmm, where did Bob R's post go that I read last night??

> Hmmmm, where did Bob R's post go that I read last night??

Probably deleted by Bob himself. This thread has gone to seed, and most people are tired of it.

Yes, I deleted it. Lots of information here, but how are we to separate conjecture and opinion from established scientific knowledge? In trying to point out reasons why a little more listing of references or other documentation would be useful, I found I couldn't do it without appearing pompous. Since there seemed to be enough of that here already, I was uncomfortable adding more. Besides, I think this thread has run its course in terms of being of value to the Mt. Whitney hiker.