Acclimatisation

[RayMondo]

Well, my first introduction to not being sufficiently acclimatised for altitude was in Chamonix. After a trip to Scotland, there I was trekking all day up the Mer de Glace in Chamonix, feeling atomic-powered and all, and even started running up the scree to the alpine hut at 10,000ft. Our route further was blocked so we descend to Chamonix at 3,000ft then cable car to around 13,000ft. I wobbled at bit, then felt fine. But then during the night, altitude sickness hit me like a sledge hammer, shivering and the rest of it. The extra 3,000ft in numbers, seemingly not a great rise. But I took four days to recover.

Anyway, I saw an excellent documentary about it. In fact ones susceptibility seems preset in each individual, and I was quite miffed to learn that even someone from a sedentary lifestyle could zip up to moderate altitude and might have no onset of altitude sickness in comparison to someone who is well trained. Though it is not generally the case. It also works the other way, as no amount of training can enable some people to acclimatise above a certain level. And that may be even a modest altitude.

Though the key to success is progression, especially over a number of years, where the body gains the ability to learn how to adapt quickly and retains a higher base level without ill effect. For big peaks, people ascend and then descend for a day or so, then keep doing this in stages of altitude until the last push or so. Beyond 25,000ft begins the death zone, where the body simply cannot maintain itself. There have been only a few ascents of Everest without additional oxygen.

So I guess biking above that is out. Well ascending, at least!

[BeDrinkable]

You know, it's a funny issue. I recently gained 10,000' in two days (2400' -> 7500', then 7500' -> 12,600'). No issues. But two years ago I was backpacking at a lake just under 8000' after gradually gaining the elevation, and it just about knocked me out. The gradual gain is definitely the way to go, at least if you're going to be sleeping at altitude, but it can strike mysteriously too! You can minimize the risk, but I think unless you live high, it's always there.

[RayMondo]

You know, it's a funny issue. I recently gained 10,000' in two days (2400' -> 7500', then 7500' -> 12,600'). No issues. But two years ago I was backpacking at a lake just under 8000' after gradually gaining the elevation, and it just about knocked me out. The gradual gain is definitely the way to go, at least if you're going to be sleeping at altitude, but it can strike mysteriously too! You can minimize the risk, but I think unless you live high, it's always there.

Still, it looks like you now have a higher base level. If one gets even slightly dehydrated, it can trgger it or serously impair performance.

Next time you'll probably be able to go higher without effect, though each of us has a limit. I expect that my base level is now elevated because I lived at over 4,000ft for many years, or at least I should be able to adapt more quickly. I'm intending to ride the Campo Imperatore route again next year, so I should find out. Although I'm now 5 years older, in terms of adapting again, it's not supposed to wear off.

[Visentin]

I am not very for the idea of going straight to Chamonix, or any other highest something of somewhere... I always prefer to do the things gradually !
I hiked in the Pyrenees for 5-6 years without never doing the Aneto. As I spent a year in Scotland as Erasmus I prefered Ben Nevis only as my last mountain (and via the ridge).. not the first like all tourist do.
As for attempting such things like Mont Blanc, I would suggest testing few other mountains above 3500 before doing it... well, it's only a personal advice.
Corax must have also some interesting experiences to tell about altitude diseases.

[BeDrinkable]

I expect that my base level is now elevated because I lived at over 4,000ft for many years, or at least I should be able to adapt more quickly. I'm intending to ride the Campo Imperatore route again next year, so I should find out. Although I'm now 5 years older, in terms of adapting again, it's not supposed to wear off.

Huh. I wasn't aware that it isn't supposed to wear out. I was actually under the impression that it essentially resets after a period of time. Thus my sister, who lives at sea level, would be at more risk than I even though we both grew up at 4400'.

[RayMondo]

For sure, after a while the blood haemoglobin level goes down when returning from higher altitude, but the ability to take a higher altitude comes more easily the more times you go. I've experienced it in the mountains and when I played Badminton in the Mexican Open. The first time I ran around up at 7,360ft, I was shagged and breathless. Without going further than sea level during the intervening year, I played again, and performed vastly better, with the same couple of days there before playing. I haven't found what this body memory effect is called or how it works, but I'll do some deeper digging.

Though I've come across a couple of references that state "When we descend, we begin losing our hard-won adaptations at approximately the same rate at which we gained them; 10 days after returning to sea level, we have lost 80 percent of our adaptations." http://www.elbrus.org/eng1/high_altitude1.htm

During my 6 years of work travel, I acclimatised better. I could be away from the Apennines, say for 1 to 3 months, but when I returned, I didn't feel slowed down with a differential of 6,000ft or so. All the many trips may have helped, and the other flights I had might have kept me topped up. At a cruising altitude of 39,000 feet, a Boeing 767's cabin will be pressurized to an altitude of 6,900 feet. I made over 500 flights.

Though not what I was referring to, this is interesting:
http://www.abc.net.au/science/news/heal ... 739204.htm

[BeDrinkable]

For sure, after a while the blood haemoglobin level goes down when returning from higher altitude, but the ability to take a higher altitude comes more easily the more times you go. I haven't found what this body memory effect is called or how it works, but I'll do some deeper digging.

Cool, thanks! It's definitely good information for anyone who spends much time in the mountains.

[RayMondo]

This thread now also on Summit Post. Numerous info coming in.
http://www.summitpost.org/phpBB2/viewtopic.php?t=49011