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Round 1 of Acclimatization: Done and Dusted

Two mountaineers navigating a glacier on a Gasherbrum II Expedition
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Sergey and Adrian arrived back in Island Peak base camp at about 8am on the morning of the 23rd of April after descending from their summit camp where they spent two nights. The three of us then walked down to Dingboche and lounged around at the lodge for an afternoon relaxing and resting before the big day that took us to Everest Base Camp. For me the rest was less deserved than for the boys as I decided not to climb Island Peak a second time. I have to admit to having succumbed to a moment of weakness…as we climbed to our High Camp on the way up, and I slid around clumsily in the fresh snow, and watched Adrian and Sergey get smaller and smaller as the intervening distance grew, and I thought about how awful I was going to feel on the way up and for the next 36 hours on the summit, and I thought about my good friend who is incredibly strong, but who recently developed HAPE at altitude….my motivation began to vanish and my self indulgent, not-so-strong, just-the-expedition-doctor-not-a-climber alter ego took hold. I reached High Camp and told the others that I wasn’t going any further. Of course I was sad and disappointed (in myself) but at times, for me at least, the right thing to do is to listen to the voice that says go down. 

So…acclimatization…What does it mean? Why does everyone do it so differently? Who does it right? Why does one schedule work wonders for some and offer little help to others? Why do some of us feel so terrible at certain altitudes whilst others feel fine?

Well, the answers to these questions are not written in stone, and in many cases, they are not really known. The “science” of acclimatization is still in many respects, a mystery. Try as we might to decipher all the changes that take place when the body is exposed to high altitude, and what they mean, and what symptoms they correlate to; there are still many unanswered questions. Nonetheless, in short, acclimatization refers to the short term physiological adaptation of the body to high altitude: and the reason we need to adapt to high altitude is because the barometric pressure drops such that the amount of oxygen available to us in each breath we take, is dramatically reduced….and we all know that oxygen is essential to our survival. It is important to differentiate acclimatization from adaptation to high altitude. Adaptation to high altitude occurs over generations in populations who inhabit the high altitude regions of the world. Adaptation to high altitude is what makes the Sherpa so much stronger than us in this world of thin air and high peaks. However, although the Sherpa people have adapted to high altitude, they still need to acclimatize each time they commence a new season of climbing. They still need to acclimatize to the extreme altitudes of the high camps and the summits. They suffer altitude sickness if they don’t acclimatize, and there are Sherpa, who, for whatever reason, are also poor acclimatizers…despite their genetic adaptation to the environment.

Most people coming to climb a high Himalayan peak have some notion about altitude sickness, and acclimatization. The one thing that everybody seems to know is that the body produces more red blood cells in order to be able to transport more oxygen…but this is only one of the many processes that go on in the body in order to allow us to survive in the low pressure environment of high altitude. I know a few more of them; in fact, I wrote an essay about them when I was studying for my Diploma in Mountain Medicine, but unfortunately, since then I have spent too much time at high altitude and the recurrent exposure to hypoxia has made too many little holes in my grey matter which makes accessing all of that knowledge an unattainable task. I can name a few of these changes without going into any deep explanations. Some occur over the first few hours, such as increased rate and depth of breathing and increased heart rate. Some occur over hours to days, such as a change in the pH of the blood to enhance oxygen delivery to the tissues, and stimulation of EPO production: and some take place over days to weeks such as the production of those oh-so-valuable red blood cells and the increase in numbers of mitochondria in muscle cells. The complexity of acclimatization is immense, and the practical difficulties of studying these processes limit our progression of understanding it completely. What we do know is that if you don’t acclimatize well, or enough, or if you don’t use supplementary oxygen, you will feel awful, become incredibly unwell and even possibly develop a potentially fatal illness and die. Everyone is susceptible to this, even a “good-acclimatizer” can develop HAPE or HACE if he or she goes to altitude too fast without taking the necessary steps. Similarly, “bad-acclimatizers” may reach a degree of acclimatization if they take their time and ascend slowly. I’m somewhere in the middle as far as efficiency acclimatizing goes, and as I have been to high altitude many many times (although not extreme altitude and never above 7000m) I know exactly what to expect of my body….I know the horrendous headache, numbing nausea, and lethargic lassitude of altitude far too well!! But even on an individual basis other factors can influence how well you acclimatize, any intercurrent illness will decrease your ability to acclimatize and make the process slower.

So…when we come to the Himalaya to try and climb one of these monstrous peaks, we need to acclimatize….and because the process is so complex and time consuming, it takes weeks. The idea is that with moderate increases in altitude the body is exposed to the reduced oxygen pressure gradually and is kick started into making the changes described above. This ultimately allows us to push the limits of normal human physiology and climb above 7 and even 8000m without dying…immediately!

By climbing Island Peak and sleeping on the summit, Adrian and Sergey have exposed their bodies to the reduced oxygen environment they will encounter on their way through the Ice Fall and up to almost Camp 2 on Everest. This means that the first time they undertake this journey, their bodies should already be acclimatized to this altitude and they will move more efficiently, more quickly and hence with much more safety. 

I have seen many people come to altitude with hopes of climbing an 8000m peak…and I have seen many people simply not ever become acclimatized enough to be able to accomplish their goal. Why this should be is a mystery, and the only explanation takes us back to our genetic make up. Some people are gifted with genes that allow them to acclimatize efficiently and well; others are not. There are a few scientific centers currently working on identifying which genes these may be and progress is being made…but it is slow, and not enough people really care! 

So for the time being we will continue to plan our ascents of the Big Peaks, in a step wise way that allows the body to adapt and proffers the suffering in bearable portions!

The next step for our Everest-Lhotse team is to take a few days rest at EBC before tackling the Ice Fall and the lofty heights of Camp 2 and 3 for further…acclimatization!

-Monica Piris, Expedition Doctor