There is much literature on permanent brain damage from high elevation -- and particularly, changes in elevation that are too rapid (i.e. not gently/properly acclimatized).

I've been considering a hypoxic chamber, for a several week use before a higher elevation climb (6000m).

However, isn't nightly sleeping in such a chamber equal to the sudden elevation change it's trying to prevent, even if gradually building up to say 3000m oxygen level?
Each morning it's a sudden transition back to sea level, then each night suddenly back to 3000m, and so on for several weeks.

This is different than acclimatizing gradually via physical elevation, where there aren't similarly sudden oxygen changes.

Am I thinking about this from a wrong direction, or does someone have an explanation for why hypoxic chambers are actually safe to use in terms of brain damage?

So you're saying if someone lives at 6k in CO Springs and works in the Pikes Peak gift shop, they're going to end up brain damaged? I wouldn't worry about it....we all will take a dirt nap in the end.

Sound sleep for adequate recovery is my recipe. Train high, sleep low...

WyomingSummits wrote:So you're saying if someone lives at 6k in CO Springs and works in the Pikes Peak gift shop, they're going to end up brain damaged? I wouldn't worry about it....we all will take a dirt nap in the end.

Well, I'm not sure about 6k, but presumably anything above 8k (according to studies) might do that. Here are some visuals for admittedly higher elevations, to underscore the changes from rapid elevation change:
http://www.auntminnieeurope.com//index. ... mID=607424

A hypoxic chamber seems to be exactly that...rapid elevation change.

peninsula wrote:Sound sleep for adequate recovery is my recipe. Train high, sleep low...

Agreed on sound sleep! This is a bit controversial, since sleeping at altitude is presumably less sound. However, interestingly, almost all quantitative studies have shown that live high, train low seems to be the most effective in terms of ensuing endurance and power output.

pjc30943 wrote:

peninsula wrote:Sound sleep for adequate recovery is my recipe. Train high, sleep low...

Agreed on sound sleep! This is a bit controversial, since sleeping at altitude is presumably less sound. However, interestingly, almost all quantitative studies have shown that live high, train low seems to be the most effective in terms of ensuing endurance and power output.

I agree that training low will be more effective in developing power. For purposes of acclimating to higher elevations, I do the opposite. The idea is to fully develop power first, then acclimate for any high altitude events.

Sure, that makes sense and seems a good strategy.
However, it's still unclear whether sudden oxygen level changes cause damage or not...especially doing it daily for many weeks.

Hmm, I dont know, if you are going to summit a 6000 m climb then that means you will only be briefly at that altitude with a night or 2 at 5,000 m??. I suspect that you are over-thinking this.

pjc30943 wrote:Sure, that makes sense and seems a good strategy.
However, it's still unclear whether sudden oxygen level changes cause damage or not...especially doing it daily for many weeks.

Unless you push the limits to the point of HAPE or HACE, I've never read anything to suggest O2 levels associated with higher elevations will do damage. It will only reduce performance. Proper acclimation will help alleviate the performance reduction and reduce the potential for HAPE or HACE.

Check out the link above for damage descriptions (one of many links you can find).

According to these studies, very slowly moving changing oxygen levels (eg during an actual climb) doesn't cause as much damage, if acclimated properly.

However, a hypoxic chamber isn't slow, it's a sudden change from 0 to whatever level it's set to. So, it seems the very act of using the chamber every day to acclimate might cause damage.

That makes sense.Good post

For several years I had access to a hypoxic chamber to train in before climbs to 6000m peaks. Note, I didn't sleep in it but would spend and hour in a treadmill/bike about three days a week for the month prior to departure. I don't think it damaged my brain any more than the occasional drinking session. I did find that it helped my acclimatisation schedule and I reasonable summiting a 6000 metre peak 7 days after leaving sea level.

Yeah, they do seem effective for sure, agreed. Congrats on such a quick summit schedule! One of the interesting points of the research articles is that there are not necessarily any observable symptoms while damage occurs, so can't really tell one way or the other based on people's observations about themselves...

pjc30943 wrote:Yeah, they do seem effective for sure, agreed. Congrats on such a quick summit schedule! One of the interesting points of the research articles is that there are not necessarily any observable symptoms while damage occurs, so can't really tell one way or the other based on people's observations about themselves...

My interest in hypoxic sleeping chambers is in preparation for the Nationals Hill Climb Championship, Pikes Peak. I've been reading more about sleeping chamber options, companies supplying such chambers, and the benefits to athletes trying to boost their red blood cell volume. Most articles recommend for purposes of boosting red cell mass, 8500 feet (2590 meters). Much higher and the benefits decrease as the body is recovering and repairing during sleep and needs a minimum level of O2 for doing the job. The article you refer to is purely about climbers that have suffered from HACE and whether or not the microhemorrhages and associated brain damage will be aggravated by future climbing. My take is if you acclimate properly, you will reduce the potential for developing HACE in the first place. In this respect, sleeping in a hypoxic chamber will help in deterring potential brain damage associated with high altitude endeavors. No where in the literature have I found any mention of HACE occurring as a result of sleeping in a high-altitude chamber set for 8-8500 feet. The only reason to not use a hypoxic sleeping chamber is the cost. I'm going to consult a sports physician on this subject and unless he recommends otherwise, a hypoxic sleeping chamber will be included in my training program.

Steve House briefly discusses hypoxic tents/chambers in THE NEW ALPINISM book, generally concluding that it was not effective at preparing him for altitude ahead of his trips.

I'm not trying to discourage you from using one, only relaying the opinion of a very experienced climber who has the money to use one regularly if it had proven effective. I'd reference the pages he discusses it so you can look up (if you have the book), but I'm at work and don't have my copy here. I believe his (their, actually, if you include co-author Scott Johnston) conclusion with respect to pre-acclimating at sea-level is that it "almost certainly does not work".