Note on Acclimatization

When I climbed Aconcagua, we tried to take advantage of the "climb up, down, then up again" paradigm in acclimatization. According to this method, you climb up above where you are acclimated, spend at least a night up high, then climb back down and spend a day or more down below. Sleeping high will send the signal to your body to produce red blood cells. Climbing back down will enable the body to produce red blood cells much faster, so for the next four days, the count will increase.

According to this theory, I should feel great on Mt. Fuji, coming from the Alps and then spending three days in Tokyo. This was so. I didn't really feel the altitude until well above 10,000 feet.

I couldn't reconcile this with another datum about high altitude climbing, which is that it can be dangerous to go down when you are acclimatized, spend time low, then climb back up. I think I realized what's happening in this case. When you go down after altitude, your cells will compress from the added pressure. You will retain the red blood cells, perhaps even produce more, now that your body is more comfortable. When you climb back up, you will feel great, not being much restrained from the low oxygen. However, your cells will still expand, and if you don't give it the time to do so slowly and uniformly, you will get sick. Edemas occur when cells of different kinds expand at different rates in the low pressure of high altitudes.