Thin Air

by in Altitude, Boundary Behavior, Environment, Hmmm..., Risk, Science

Mount Sanford (I think)

“I am nothing more than a single, narrow, gasping lung, floating over the mists and summits.”
-Reinhold Messner, Everest: Expedition to the Ultimate (1979).
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Air

When I was a teen, my dad spent two months preparing to reach the summit of Denali in Alaska, the highest peak in North America at just over 20,000-feet (about 6,200-meters). A physician, he was well aware of the need to acclimatize to the altitude.

During that time, I accompanied him and several others to the summit of Mount Sanford, at just under 5,000-meters, the highest elevation I’ve ever reached. I was fairly well acclimatized up to 3,500-meters at the time. Still, I well recall the thin air during the last day up to, and back from the summit.

A month in Japan, mostly in near sea-level Tokyo and Osaka, and I’m reminded that the Earth’s atmosphere is little more than a thin blanket. And the oxygen that I like to breath accounts for only about one-fifth of it.

Still, the atmosphere presses with almost fifteen pounds per square-inch (14.7 “psi”) at sea-level . The weight of all the air above, that’s more than a ton per square-foot!  And though we don’t notice, our bodies push back with the same force.

Travel higher, and there’s less air above. So air-pressure decreases with altitude, by roughly one-half for every 18,000-feet (5,600-meters). At around 63,000-feet, it drops to a mere 0.9-psi, not even enough to keep human-body temperature water from boiling. (The “Armstrong limit”.)

Aside from keeping the fluids in our bodies from vaporizing, atmospheric pressure also pushes oxygen molecules close enough together for breathing. But with only half the pressure at 18,000-feet, only half as much oxygen is available as at sea-level. And at 29,000-feet, or the summit of Mount Everest, it’s only about one-third. And that’s not enough for human life.
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Humans at Altitude

In the US, I live at around 6,300-feet (≈2000-meters), so there’s about 20% less “oxygen pressure”. That’s enough to affect the human body, especially when exercising. Humans can adapt; but it takes time. And a month at sea-level is more than enough time to lose that adaptation.

Those not adapted may reflexively breathe more deeply (“hyperpnea”), or faster (“tachypnea”), and the heart may beat faster (“tachycardia”). But this can throw-off blood “pH” (acidity or alkalinity), eventually leading to a medical condition known as “alkalosis”. But this is only temporary.

Over about a week, kidneys will work to re-balance blood pH, a process that mountaineers can speed up with certain drugs, such as acetazolamide. But the kidneys also respond by secreting a hormone called “erythropoietin”, or “EPO”.

Most notably, EPO causes a gradual increase in red blood cells [“hematocrit” on a blood test]. Blood plasma also decreases, and more capillaries form in skeletal muscles. And the heart’s right ventricle may enlarge, increasing blood-pressure to the lungs. This all helps to more efficiently move oxygen.

Traveling to high altitudes without giving the body time to adapt can cause an illness known as “acute mountain sickness” (AMS). Severity can depend on elevation change, altitude, and rate of ascent. But AMS can be deadly.

Most who ascend from sea-level to 10,000-feet will experience some AMS symptoms for a few days, usually a headache and fatigue. Severe headaches, nausea, and difficulty with coordination might require descending to a lower elevation.

An inability to “get enough air” even when resting, and severe difficulties with coordination require immediate descent and medical attention, as they signal two potentially lethal forms of AMS.

A common thumbnail calculation for the time needed to fully adapt to an altitude is to multiply the elevation-change in kilometers (1,000-meters) by 11.5 days. So to fully adapt from sea-level to my home in the US at about 2,000-meters should take around 23-days.

Likewise, adapting to Base Camp at Mount Everest at around 5,200-meters (about 17,000-feet) should take about 60-days, assuming a start from sea-level. However, that pushes a limit. Most healthy humans can only adapt to long-terms up to about 5,000-meters (16,500-feet).
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Thin Air

The summit of Everest might now be reached by hundreds each year. But only a handful have done so without supplemental oxygen. Elevations above 8,000-meters are commonly called the “death zone” due to the thin air. In fact, until the mountaineers, Reinhold Messner and Peter Habeler, reached Everest’s summit without supplemental oxygen in 1978, it was a feat considered impossible.

Still, after months of acclimatization, the two mountaineers only barely succeeded. Falling to their knees in the snow to catch their breaths, Habeler began hallucinating. And Messner later described feeling as though he had lost his sense of “self” before literally crawling onto the summit.

In a later recollection of that moment, Messner declared that, “In my state of spiritual abstraction, I no longer belong to myself and to my eyesight. I am nothing more than a single narrow gasping lung, floating over the mists and summits.”
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V̇O2 max

“V̇O2 max” is a measure of how much oxygen a person can utilize during a physical activity; and it’s constrained by the rate of blood oxygen transport. Many aerobic athletes, such as bicyclists and runners, will train at high altitudes in the weeks before events to naturally increase this capacity. However, the use of synthetic EPO to artificially induce the effect is almost universally banned in sports as a form of “doping”.  But there’s an odd gray area.

“Xenon” is a chemical element with the atomic number 54, and symbol “Xe”. It is a dense, colorless and odorless “noble gas” found in very small amounts in the Earth’s atmosphere. As a noble gas, like helium or argon, it’s generally non-reactive. However, the atom’s large size allows for some weak chemical interactions, including some that affect the human body.

Most importantly, breathing xenon can easily prove fatal. Not only can it displace the oxygen necessary for life, but high concentrations will also put a person to sleep in seconds. In fact, xenon is used for general anesthesia by trained physicians with proper equipment and careful administration. But a side effect is that it also stimulates the body to produce EPO.

The Russians apparently tried this with athletes at the Sochi Olympics, causing the World Anti-Doping Agency (WADA) to later ban xenon use. But whether xenon-elevated EPO really improves performance is still an open question, with no scientific studies demonstrating any advantage.

Regardless, four British military veterans just summited Mount Everest in a single week by using xenon to boost their red blood cell count while at sea-level. Under medical supervision, the four men inhaled a xenon-oxygen mix in a single administration that lasted less than an hour, with the hope that the greatest effects would occur 10 to 14 days afterward.
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Gas

Personally, I think this is mostly a stunt, with media (again) treating a press-release as “news”. The four men have also been sleeping and exercising for weeks in low oxygen environments, simulating the high altitudes. So this was more likely how they pre-acclimated their bodies. Still, Reinhold Messner has expressed his support of the process, including the use of xenon. 

These guys did manage to make it from sea-level to the summit of Mount Everest in a mere week, a record to be sure… with months of medically-supervised preparation, a massive support team, and supplemental oxygen. To what extent this represents a “human” endeavor I suppose depends upon what technologies one considers as a part of the human identity, whether high-tech clothing, synthetic ropes and aluminum ladders, bottled oxygen, or medically administered xenon gas.

The whole point of “mountaineering” was once considered to be the challenge. Granted, I’m nowadays happy to make it up a local hill to enjoy the view. But Mount Everest, at least, seems to have been reduced to the status of reaching the top of a tabloid news cycle with an expensive selfie.

 

References (though there’s plenty of media coverage):

Dias, K. A., Lawley, J. S., Gatterer, H., Howden, E. J., Sarma, S., Cornwell, W. K., Hearon, C. M., Samels, M., Everding, B., Liang, A. S., Hendrix, M., Piper, T., Thevis, M., Bruick, R. K., & Levine, B. D. (2019). Effect of acute and chronic xenon inhalation on erythropoietin, hematological parameters, and athletic performance. Journal of Applied Physiology, 127(6), 1503–1510. https://doi.org/10.1152/japplphysiol.00289.2019

Horwath, H. (2020, January 3). Blood Doping and EPO: An Anti-Doping FAQ | USADA. U.S. Anti-Doping Agency (USADA). https://www.usada.org/spirit-of-sport/blood-doping-epo-faq/

Malcolm, C. (2021, December 30). Into thin Air: The Science of Altitude Acclimation. iRunFar. https://www.irunfar.com/into-thin-air-the-science-of-altitude-acclimation

UIAA Medical Commission. (2025, February 5). Statement on xenon and high-altitude mountaineering – UIAA. UIAA – International Climbing and Mountaineering Federation (UIAA). https://www.theuiaa.org/statement-on-xenon-and-high-altitude-mountaineering/

Wilkerson, J. A. (1985). Medicine for mountaineering. Mountaineers Books.

 

 

24 thoughts on “Thin Air”

  1. I’m out of breath just reading this. I’ll leave Mount Everest up to others. My highest mountain was a 10’er, and that’s good enough for me. Whenever I visit relatives in Colorado, I end up getting a headache. Now I know why. I need some Xenon and EPO.

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    • Relatives in Colorado… I don’t know whether to recommend drinking lots of water with some acetazolamide, or a lots of whiskey with a handful of ibuprophen.

      The only time ever been really slammed with AMS by the altitude was going up San Jacinto, down near you. About 10,800-ft (3,300-meters), if I recall. At the time, I was going to college at sea-level, and we rode the tram up to like 8,500-ft from Palm Springs where we started the hike. Acclimatization makes a big difference. Regardless, I’ve never had much interest in the gasping-for-air effect of hiking above 5,000-meters.

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      • Mount San Jacinto was my 10’er. I’ve done it twice, although the last time was 20 years ago.

        My wife hiked it with me, and she stumbled and fell twice, hitting her head on a rock, each time. By the time we rode the tram back down, she had a big hematoma on her forehead, and a black eye. Everyone was looking at me like I was some kind of villain.

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        • You’d have my respect… Except for the black eye thing. 😉

          Decent hike. I think San Gorgonio was a little higher… 11,500 ft? I recall reaching that summit in a storm with not much more than a windbreaker. We were the only people dumb enough to be on the summit. :p

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  2. Hyperpolarized (by optical pumping of angular momentum) Xe MRI was a big thing for a while for lung imaging. Have not kept up. There must have been some spin-offs, so to speak.

    We seem to take a week or four to acclimatize to heat and cold too.

    Faster horses. Younger women. Older whiskey. More money.

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    • Yes about the temperatures. Takes me several weeks either way. But adapting to the cold seems easier.

      Don’t know much about the MRI tech (or the younger women), but sounds interesting. Xenon is an odd element. I watched a clip of a guy getting high by breathing some. Looked like an 8-liter bottle… $90,000 for the bottle’s contents! He commented that the four breaths he took cost several thousand dollars.

      It’s apparently considered an ideal general anaesthetic since it’s completely out of one’s system in just three hours. Just too expensive to use.

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      • Low concentration (0.086 ppm) in the starting material, air, explains the cost. But why is there so little Xe on Earth? Apparently there should be more. Xe: the missing years.

        Low altitude acclimatization seems somewhat like cold acclimatization—maybe a bit easier. But the process can still apparently take weeks. Fewer people living at very high altitude may bias our interest.

        One might naively expect risks with more red blood cells.

        pmc.ncbi.nlm.nih.gov/articles/PMC3641122

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        • I do take some aspirin every day. But from the more thorough medical literature, I understand that the body also produces more nitric-oxide, dilating blood vessels. Something (?) also apparently stimulates an increase in mitochondria in skeletal muscle cells. There’s a lot more going on than just red blood cells.

          Anecdotal, but it makes a significant difference for me. At sea-level, I can easily take 20-seconds off each mile on a flat 10k… for a few days. After descending, it’s very apparent that I’m dumping iron. I’d say it only takes about a week to lose the local serum acclimatization.

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          • That’s an interesting link. I’ve never heard of “High-Altitude De-Acclimatization Syndrome”. It looks like the people who were studied went down from about 3,600 meters (12,000 feet) either to about 1,600 meters (1-mile) or about sea level. That’s decently high altitude to stay at. I probably wouldn’t be able to sleep very well for a few days at least. Maybe some AMS symptoms?

            I’m usually at about 4,500 ft. I don’t think I notice much difference after going down to sea level. Except, I know what LT means about “dumping iron” (in the toilet). But I don’t run. At least not if I can help it.

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  3. Sorry, but not surprised in this age of game show mentality, to hear about the Xenon stunt on Everest.

    This post certainly got my mind racing about altitude given that I’m headed to Peru in a couple of months. Cusco at just over 11,000 feet seems mild compared to what you’re talking about, but the elevation around where I live is only about 300 feet, barely above sea level, and I won’t have weeks to acclimate. Any suggestions?

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    • Take care at the altitude. You can read my first comment about the only time I’ve ever had my butt kicked by AMS symptoms… mostly headache and nausea. The rate of ascent can be more important than the altitude. I live high enough here that I don’t have any problem at the tops of the local peaks (around 11,000-ft). But I do really feel the elevation on the 14-ers to the south. I lost my lunch coming down from Whitney (the “religious experience” in my post about the “Mountaineers’ Route”). But sleeping at high altitude is usually the biggest issue for me.

      Drink lots of water… more than you might think you need. It helps your kidneys process down the blood pH. Acetazolamide, or “Diamox” is the usual mountaineers’ pre-treatment. It’s usually taken before travel if you’re concerned… something you can mention to a doctor. Also (and this is not a medical recommendation), I understand that chewing a small amount of the local coca leaves does actually help if you’re not feeling well.

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      • Thanks. I’ll plan to drink a lot of water. We’ll see about the local cure-all. I’m looking forward to the trip, which also takes me to Machu Picchu and the Galapagos.

        Japan’s islands, Taiwan, southeast Asia, and maybe Mongolia are on my tentative list for next year.

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        • I think you already know that Taiwan is one of my very favorite destinations… Great cities, food, wilderness, culture and people. Someplace I’m happy to revisit any time.

          While we were in Okinawa several years back, my husband arranged a two-day tour of the ancient castles on the southern part of the island. It was just something a local taxi driver had set up (I had to do a lot of translating). Turned out, he was a real expert… Fascinating!

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  4. Yes, mountain climbing isn’t for me. I remember being in Colorado when I was a young teen, and my mom had a lot of trouble with the altitude there.
    Thanks for explaining so well what happens when we are in higher altitudes and how to prep your body.
    I agree, it’s sad about the lengths people will go to to take the challenge out of something.

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    • Edited 5/25: It wasn’t the Sanford Glacier, which I stated earlier (and which is a steep, technical ascent). We went up the “North Ramp” route up the Sheep Glacier. It wasn’t technical (other than watching for crevasses); but it was slow. I think serious climbers go up in a day or two. I don’t know how much you already know…. We were there for six nights. The point was acclimatization and staying in an ice field environment, so there wasn’t any hurry. Big packs and sleds. Climb high, sleep lower, climb higher, sleep a little higher… periodic trips to the bottom of the ice-field to retrieve sledded supplies and ferry them higher. Lots of skiing, roped on the glacier. The summit is pretty big and flat. I think there were maybe four or five other groups on the mountain doing the same thing. I guess it’s part of a routine or sequence for Denali prep?

      A couple of times, I had to stop while skiing downhill near the summit so I could catch my breath. I was fine at rest. But I remember thinking it was just high enough to put a somewhat surprisingly lower hard-limit on sustainable exertion.
      I was also in good shape… from running in high school. 😉

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