Acclimatization on Pobeda
When we climbed Khan Tengri in 2017, we were very positive about our experience with pre-acclimatization at home with the Hypoxic tents from https://altitudedream.com (see blog 2017). This enabled us to climb Khan Tengri in one go, without having to pass the icefall multiple times - the section with the most objective dangers of the route. How was our experience with the hypoxic tents this year?
I noticed some differences between this year and 2017. My sleeping program was the same, but due to my busy schedule I had less time to do the passive and active acclimatization with the mask. Passive acclimatization means just sitting down and using the mask on the highest setting (6.400m) - 5min on, 5min off for an hour or longer. Active means using the mask when training on a home trainer, which is very intense. The other difference was the time between pre-acclimatization and arrival in basecamp. In 2017 we were within a couple of days in basecamp after our last night in the hypoxic tent, while this year it took a week.
The first test if we were pre-acclimatized or not was when we arrived in basecamp at 4.000m by helicopter. We felt pretty good! This was a good sign. Of course, you have to get used to doing everything at a slower pace and you definitely feel the lack of oxygen. But in general we felt good - no headaches, sleeping fine and good appetite. This meant that the hypoxic tents had done their job!
The real test came when we went from Khan Tengri C1 at 4.200m to C2 at 5.400m. This is a significant change in altitude. Acclimatization is very personal and is a completely different process from person to person. For example I never have much problems at altitudes up to 5.500m and can be pretty quick, while Gijs/Martin seem to have much more difficulties around these altitudes. However, above this it can be the complete opposite. I feel completely empty, while they can march on, seemingly without much problems. This happened on Khan Tengri. The trip towards C2 was realtively easy for me. But after arriving I felt shitty for several days and was not even able to reach C3, while Gijs and Marin felt fine and made two acclimatization trips to C3. This was very strange to me. In 2017 I felt fine in C2 and had no issues, this year I was having really bad headaches and was extremely slow when trying to go up to C3.
As a combination of my slow acclimatization and the bad weather we were not able to follow our acclimatization plan. We wanted to get at least one night sleep at 6.400m, but eventually only slept at 5.400m for three nights and then went back to BC, knowing we would have to put in another acclimatization rotation on Pobeda before going for a summit attempt.
Our first acclimatization rotation on Pobeda was very tough, as you can read in this blog. During this trip I felt much better and was able to make the first tracks for a significant part of the route towards C2 at 5.200m trough deep and heavy snow. Gijs and Martin were completely broken that day. But again, the days after the roles were turned around, although I felt much better than on Khan Tengri. In the end we reached 6.300m, without any of us having significant altitude problems. Our plan was to sleep at least at 6.400m, but preferably at 7.000m during this trip, but due to the heavy snow we were forced to descend.
Once back in basecamp, I wasn’t sure if these two acclimatization rotations were enough for a summit attempt, during which you normally sleep for three nights above 7.000m. But we didn’t have much of a choice and would just go and find out how we would feel. Unfortunately during our summit attempt we didn’t reach an altitude higher than 5.600m and we never found out.
This expedition was quite difficult from a strategic point of view. How to get enough acclimatization to safely sleep during the summit attempt for 3 nights above 7.000m? How not to waste energy by always being the first and having to make tracks through the deep snow? How to balance the use of energy, the weather forecast, the amount of food (=weight) to take and proper acclimatization? Is it better to stay high for a longer period knowing this will deplete your energy or better to descend earlier instead to take rest in BC? This year finding the best strategy was a big challenge, being a daily topic of discussion in the group.
Did the pre-acclimatization work? Definitely! However, I noticed my body reacted differently this year than two years ago. I believe my pre-acclimatization was less than in 2017, because I put less effort into the active and passive hypoxic training. Would I use this strategy again next time? Depends - if I have time to acclimatize in the alps or on a real mountain, this is of course always nicer. But if I don’t have this option, then yes, for sure I would!