Mt. Whitney Portal Store & Hostel Forums General Mt. Whitney Portal Store Message Board How fast does the body "deacclimatize"?

If people are buying all this gravity talk, next time we'll try convincing 'em that the pull of gravity is not particularly weaker (ok, 10% weaker) at the altitude of the International Space Station than it is at sea level.

If I have not been up to the Whitney area all winter, getting to the portal at 8:00 pm and sleeping until 3:00 am is not enough time to prevent serious altitude issues above 13000 feet the following morning.

If I have been on multiple hikes above 10000 feet (even once a month) for 3-4 months leading up to a Whitney Hike, I can show up at the portal, sleep for 6-7 hours and go for the summit. So even though I am at sea level most of the time, and shouldn't have any residual elevation adjustment......you actually do.

I haven't figured it out yet, but I don't think all the benifit of spending time above 10000 feet goes away immediately.

That's a good point, I've experienced very similar results.

I'm not sure if it's acclimatization or some other (rather nebulous) neurological process that causes the improvement.

For example, I also find that if I'm accustomed to running at a specific pace, the first time I train at a faster pace I think I'm gonna die. The next time I train at the faster pace, it feels much easier and indeed my heart rate stays lower, but I can't have physically improved significantly from 1 workout just 24 hours earlier. But something is happening.

In any case, I enjoy the physics and the personal anecdotes everyone is posting.

I'm still surprised that there's no direct mathematical expression that represents the overall acclimatization and deacclimatization (I realize this would be a composite score representing several combined adaptations that the body is making simultaneously). Surely such a curve exists.

For example, of the total improvement possible, what percentage has taken place after 24 hours? After 48? 72? A week? Two weeks? I would imagine there are reliable charts that mountaineers use regularly to estimate their adaptation. Otherwise, for those preparing to do Everest, how do they know when to leave each camp and move to the next camp higher up to begin the next stage of acclimatization? They suddenly wake up 6 weeks in and say, "Today seems like a good day"? Or do they go very specifically by blood oxygen saturation levels?

It sounds to me like some of you out there really know a lot about this - is there no such generalization that can serve as a rule of thumb?

"reset pulmonary/ventilation sensors" change in days
tuned up somatic muscles will begin to detune in a week
polycythemia (more red blood cells, assuming you had been high enough and long enough to trigger this benefit) may last for a month.

h_lankford posted these factors (and another one that will probably never pertain to my activities), so clearly he knows a whole lot more than I do. Can these adaptations be tracked, and their combined effects charted as a percentage of complete adaptation? Or am I somehow oversimplifying this?

z

zip, we are getting pretty deep in this thread. someone is gonna tell us to stop soon. There are some lengthy as well as some practical answers to your good questions. Yes, going to the Andes and Himalayas does require thinking about how long it takes for the body to adapt. Otherwise, you cannot push unwilling flesh up the mountain. Ballpark figure is that you don't usually push above 20,000 until you have spent 2 weeks acclimatizing. Some people need more or less than that. Some never adapt. There is a tremendous amount of individual variation. Full acclimatization takes over a month, but not getting to the extent of those who have lived there for years. I just returned from 3 weeks in the Sierras. What I could do at the end was simply phenomenal compared to the first day. Never ceases to amaze me. Have lost it all, though, in one week back here at sea level and 90% humidity, ugh, ugh. Harvey

I can refer you to these bibles:

Hultgren, High Altitude Medicine 1997

West, Schoene, Milledge, High Altitude Medicine and Physiology, 4th edition 2007
page 44. "A rule of thumb often given is that above 3000m each
night's camp should be 300m above the previous one and that
every 2-3 days a rest day be added." (This is a well known
rule and jibes with my comment earlier about 20,000 ft.)

page 46 re: carry-over acclimatization
"These studies support anecdotal experience. The effect of
acclimatization probably falls off exponential with time over
2-3 weeks, though some feel there is residual benefit even
after months." (Hence, my earlier comment that there is a
tremendous amount of individual variation.)

As for human performance and mathematical formulas, I will paraphrase one of my witty medical mentors by saying that
" predictions are an unending series of assumptions based on intuition and inadequate facts."

I think Kashcraft and Zip are talking about the body's "memory" in terms of how their body responds to Altitude. They are not talking about being adjusted to the elevation in terms of the Blood carrying more oxygen or the strength that comes from being at high elevation for a week or two. This permanent adjustment would exist in a person who lives high for a long period of time.

I read their comments to mean that if they have hiked frequently, they don't get altitude sickness as quickly. This would be stage 1 altitude sickness, including loss of appetite, headache, nausea, fly like symptoms.

As an example if I drive to the portal after a long winter and begin immediately hiking, I will peak out about 10000 - 11000 feet before I come down with flu like symptoms. If I have hiked recently at higher elevations, I can often hike immediately to 11000 - 12000 feet to make my first camp. Based on the research available, most elevation adjustment from my hike three weeks before would be gone.