(Video: Rick Armour, Michael Bocsik, Gord Knox, myself, our guides and some of our porters near the summit of Kilimanjaro. While this video might serve as a small example of pressure breathing and rest stepping, it is not the best example. We'll be providing some good demonstrations in the near future.)
It all make sense however; use your lungs -- completely--, and at the end of each exhale, create negative pressure in your lungs, and move very, very efficiently. If you have an SPO2 meter you can actually see how subtle variations in breath style and moving style change your hemoglobin saturation. I found that there is a big difference between my "walking" SPO2 and my "standing" SPO2 at 3000 meters. There is an even larger difference above 5000 meters. Simple limb movements use oxygen in ways that you can see it on the meter.
One of the striking characteristics of pressure breathing is the frequency of breaths per step and how the ratio of required breaths per step actually changes depending on the altitude. At approximately 4000 meters, I had to take 2 or 3 steps per breath-- if I took fewer steps, I would actually get light headed. If I didn't pressure breath while I was moving, my SPO2 levels would drop to the 70's. If I pressure breathed my SP02 levels were in the high 80's. Let's just say that I maintained my levels in the high 80's and low 90's for my own health and fear of "brain fog". At the summit of Kilimanjaro, I actually was completely comfortable doing 1 pressure breath per step and by doing so, I could maintain a level of 86%. To get this high of an SPO2 however, I was required to move very, very efficiently. As soon as I would increase my stepping rate, my SPO2 levels would fall. Taking a very big breath and exhaling at sea-level over and over again is nearly impossible to do at sea-level -- I've tried. At sea-level it actually makes me want to puke and fall over sideways.
Will I do this again? The plan is to get in touch with some more altitude people and share information. I will be at altitude again. This whole experience has opened some exciting new doors in both my professional and personal life and now find myself with new collaborators and new friends. I'm very happy to be in this place. The video that I have been recording is being shipped (200 GB of high definition video) to a new colleague of mine who works in the film world. We'll see what we can put together in our spare time...