What Does Altitude Sickness Do to the Human Brain?


As if climbing a mountain wasn’t hard enough
already, forcing the body to acclimate to high altitudes too quickly can not only stop
someone from reaching the summit, it can have dire consequences. But altitude sickness doesn’t just affect
adrenaline-driven mountaineers. The effects of altitude sickness
can be experienced at as low as 1,800 meters, only about a third of the way up to Everest
Base Camp. Oh and just because someone is young and physically
fit, doesn’t mean that they won’t get sick. Youth is no protection. Fitness is no protection. It doesn’t work that way. My name is Jan Stepanek. I’ve been at Mayo Clinic for the last 25 years,
I’m an internal medicine and aerospace medicine specialist. The biggest difference between low altitudes,
like sea level, and high altitudes, like a mountain, is actually not a lack of oxygen, it’s the
change in atmospheric pressure. We all think of oxygen merely in terms of
what is around us. 21% of the ambient air that we breathe is
oxygen. That percentage doesn’t change between sea
level and Mount Everest. The only thing that changes is the pressure
that surrounds us. It’s this pressure that drives the gas exchange
from the lungs into the red blood cells which carry oxygen to the rest of the body. So less pressure at a high altitude means
it’s harder for the body to take up the oxygen. But… Our bodies are amazing. The body can adapt to the lack of ambient
pressure at high altitude by breathing faster and elevating the heart rate. By blowing off more carbon dioxide, the lungs
are able to enrich the blood with more oxygen. It’s called sympathoadrenal drive, so your
heart rate and your cardiac output goes up and that allows your body to gradually reset
to that new altitude environment of decreased ambient pressure and you still continue to
function well without falling ill. This all happens seamlessly if you ascend
to a high altitude slowly. It’s when you jump from low to high too
quickly that the body struggles with the change. This causes the first type of altitude sickness
you’d experience called acute mountain sickness with symptoms of headache, lack of appetite, nausea, vomiting, fatigue, light-headedness, and disturbed sleep. But if you breathe too fast you can start to lower your carbon dioxide levels and there is a balance. You need normal oxygen and carbon dioxide
levels in order to function optimally. And it’s these low carbon dioxide levels
that can start to cause problems. The carbon dioxide we all think of as being
a waste gas. But we actually need certain levels of carbon
dioxide to maintain normal blood flow to regions of the brain. So if carbon dioxide levels drop too much,
blood flow to the brain starts to diminish. The changes in oxygen levels and result in changes of breathing can cause the more dangerous forms of high altitude illnesses, HACE and HAPE. We believe today, based on the pathophysiology,
that from acute mountain sickness, and if not paid attention to and people do the foolish
thing and continue to ascend despite being sick, then you can progress to high altitude
cerebral edema, which not infrequently goes hand-in-hand with a little bit of pulmonary
edema. These two edema illnesses are rare and can
be difficult to study because they often occur in high, hard to reach places where the person
either rapidly descends and their symptoms ease or they progress and cause death. In high-altitude cerebral edema, experts think
that the changes in blood flow causes an increase in the permeability of the blood-brain barrier
causing brain fluid to leak around the blood vessels. This causes the brain to swell and starts
to hinder the central function of the brain stem and other critical areas of the brain. But what exactly causes the blood-brain barrier
to leak? Million dollar question. You know, there is a lot of hypotheses. Similarly with high-altitude pulmonary edema,
blood vessels constrict in the lungs in a patchy fashion in response to lack of oxygen. This can cause the vessels to leak in a manner
similar to the blood-brain barrier resulting in pulmonary edema. And keep in mind, this is in an environment
where you already have lack of oxygen due to ambient pressure, so it gets to a point
where it just gets to be not enough for the body to be able to function and systems start
shutting down, arrhythmias start happening, and people go into respiratory arrest. So this is the worst case scenario. But for many people, acute mountain sickness
is more of an uncomfortable headache that gets better over time or after they move to
a lower altitude. You can prevent altitude sickness just by
taking more time to move from low to high elevations. You know, the biggest challenge I think that kills more
people on mountains these days than altitude sickness is bad judgment and a sense of, “I’ve
paid for this trip, it cost me a lot of money, I’m here and by gosh I’m bagging this peak.”

75 thoughts on “What Does Altitude Sickness Do to the Human Brain?

  1. I've always wondered why people got sick in high altitudes. I was never one of them, I'm just thankful because my sister always spills her guts out every time on flights.

  2. Reminds me of the day I landed at Cusco on my way to Machupichu, just minutes after landing my hands and feet felt very numb and tingling, I also had lost strength to carry my bags, pretty scary at the moment. It took me 2 days to feel better up there.

  3. people in the Andis disprove two things. Race is a Social constructs.
    And The basis for evolutionary psychology is what happened thousands and millions of years ago. And nature does Change. But Humans the Andis . Although it's their blood that changed . The principle is debunked. The mind brain and Motablism are some of rge fast'es systems to change with in an individual . And we don't even know what happened thousand and millions of years ago just look at what we know about neantherhals . And can we see this in other Species. Instincts for environments they haven't lived in for thousands and millions years. And how do you falsifie evolutionary psychology.
    I when it comes to analyzing thought evolutionary psychology is actually very distracting. What happened thousands of years of years ago was just that.
    And i looked up the dictionary definion of racist.
    To believe a race is partice are some way based on race . So being Immune to skin cancer is racist surviving high outatoods is racist. Genetics are reality is racist

  4. Hi seeker
    Another interesting and educative video..
    I thought because of oxygen we get mountain sickness…
    And taught in school like this.
    But now i know it is due to atmospheric pressure…
    Thanks for clearing and correcting us…
    I always like this sick related video..
    Thanks seeker…🙏
    You are best…👍😊

  5. physical fitness IS important. physiological transformations due to aerobic exercises will shorten your adaptation time.

  6. good video, I really have never looked at oxygen being the same percentage due to comments by climbers saying it is the oxygen levels that are the issue; but it does makes sense that it is the lower pressure that causes the body's available oxygen…I found that after being in the Andes and other ranges I don't have any particular bad effects from the lower pressure at least at the 10-12 K altitudes…thanks for sharing

  7. How about doing a video about shingles? After talking to a few doctors around here I get a lot of, "We don't know, but if you find out something, let us know".

  8. I live in Texas, I have extended family that live in New Mexico. I get sick every time I’ve visited there, and my nose spontaneously starts bleeding on the trip back to Texas.

  9. I live in a mountain town at roughly 2000 meters/6500ft and tourists get sick coming up here all the time.

  10. There are a lot of "home remedy" sites that claim that ginger helps with altitude sickness. Is there any truth to this?

  11. If you have a larger "lung capacity" will you have less effect of Mountain sickness?

    From A&P, I have one of the largest lung capacity. I'm just wondering if that would effect getting sick?

  12. High altitude sickness is no joke. I experienced it while visiting Peru, and it was honestly the worst pain I’ve ever felt.

  13. Question: how would you mitigate this symptoms if you are flying from, let's say, California (low altitude) to Colorado (high altitude)?

    I can't really control how slowly I ascend to the state.

  14. His comment at the end is the most important. What kills people is the sunk cost fallacy, the idea they've already put so much into it they can't stop now, not fully comprehending their life is at risk.

  15. I used to get mild sickness in Bogota Colombia, and Quito Ecuador. But when I was in La Paz Bolivia I could barely get out of bed. I never felt so bad before. There are some medications for this, but ED drugs like Cialis or Viagra actually help very well also.

  16. The percentage of the oxygen in the air might be the same. But the lower density of the air because of the lower pressure means that there is less oxygen per volume of air. So that should also make it more difficult to get enough oxygen in the blood. Not only the pressure itself helping less to "push" the oxygen into the blood (if that is how it works).

  17. Altitude sickness sucks, I went from 700 feet elevation to 8700 feet in less than 24 hours. I had a massive headache, I could take more than 3 steps without being out of breath and having to put my hands on my knees. Thankfully I woke up the next morning just fine and have since learned my lesson on how my body can adjust to altitude

  18. So what would happen if you like lived on mountains Everest and the sudden went to sea level, would you be fitter/moractic?

  19. I think this has to do with genetics also, I was born near sea level, and have lived in low lands most my life, usually not far from the beach. when I started hiking, I went to the smoky mountains, and even the highest peak on the AT trail, Clingmans Dome, but this was only about 6,600 ft. I had no i'll effects other than being tired of lugging a 50lb backpack up it.

    I wanted to see if I would get sick, or feel any negative effects at high altitudes, so went up a few mountains in the Rockies, then I even tried to sleep out in the open at over 12,000 feet. and I did not feel anything strange. but I wasn't physically hiking at that altitude. years later I hiked up a mountain in the Caribbean, this peak was over 10,000 ft. and very steep climb. all I can say is these altitudes just make me more fatigued, you need to breath harder and longer, to catch your breath. and was exhausted, but all this is what I would expect since you do not have the same amount of oxygen getting into your body. lucky for me I did not experience nausea or dizziness.

    But I have heard of others getting seriously i'll. or dizzy.

  20. Great video, I've suffered this before. I did find the audio difficult to understand largely due to the music choice and volume

  21. Once you have lived in high altitude, places(above 3000ft), you should not have a problem adapting. The only ones having a problem are the ones who have lived near sea level all their lives. I prefer living in a place surrounded by mountains to the seaside. This video is one sided, for people living at lower altitudes so why isn't that mentioned?

  22. Thank you for the video.. As a normal person, I also want to know what the climb speed is so that it is not too fast and safe for human..

  23. Hmm 🤔 not quite sure that's correct, what about those people who live in the highest places in the world? Took years for them to adapt yet they still haven't fully been able to live there without problems, many generations after the first people settled there and they still have people coming to a doctor for altitude sickness, there's a lot more to it than this "expert" is trying to say… 🤦‍♂️💥 🛎

  24. I've had acute mountain sickness, coming down from a height too fast and honestly I felt like I was dying. My skull, apart from having a headache that rang like a church bell with every heartbeat, felt like it was being slowly detached from my spine. Vomiting felt like I was trying to heave my internal organs up, dizziness was so bad I couldn't sleep or stand up and painkillers don't work because you can't keep them down in your stomach for more than a few minutes.

    At a few moments I actually nearly said out loud "someone kill me now"!

    The bends must be one of the worse ways to go..

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