Altitude sickness? Dehydration? Other?

1:00 p.m. on May 31, 2009 (EDT)
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Hey all,

While hiking up I had pins and needles in one leg while hiking which I kept stopping to stretch, this is a first for me, it went away after about an hour of stretching stops but I'm unsure if the stretching fixed it. Near the top I had a pretty good sized headache, before hiking to the summit I took some advil and layed down for a half hour/hour and it felt a bit better but was still there, on the way down it was still pounding. My vision/balance was a little off as I can remember looking over at something far away and sort of having it swirl/turn. I made a pretty bad decision while hiking when I lost a trail to keep going thinking "oh it's probably over there" and kept going for about a half hour/hour which is uncharacteristic of my style of hiking (though it might just be me being an idiot, I'll fully admit).

So, here's what I did. I live at sea level, in the morning I drove up to 6,500ft, then hiked within 4-5 hours up to 11,000ft. I've done this at a slower pace (hiking up) before a few times without any issues other than being dog tired. I chugged a lot of water (liter and a half) in the morning before going, brought a 3 liter camel pack which I sipped the entire way through, finishing as I was going to my car. Peeing during this trek seemed fine, mild coloring, this morning = heavy coloring after drinking another liter +12oz water after getting home. I ate oatmeal for breakfast, had three cliff bars, a can of tuna, three ounces of dried cranberries, and a half bag of jelly bellies while hiking (all but the oatmeal).

Any ideas what the hell happened? This is all new to me and the pins and needles is really weird when not sitting down. Any ideas or if you've had similar would be really nice to hear. Thanks for reading.

2:00 p.m. on May 31, 2009 (EDT)
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Sounds like mild AMS.

Headache is a primary symptom used to diagnose altitude sickness, although headache is also a symptom of dehydration. A headache occurring at an altitude above 2,400 meters (8000 feet = 76 kPa), combined with any one or more of the following symptoms, can indicate altitude sickness:

Lack of appetite, nausea, or vomiting

Fatigue or weakness

Dizziness or light-headedness


Pins and needles

Shortness of breath upon exertion

Persistent rapid pulse


General malaise

Peripheral edema (swelling of hands, feet, and face).


The amount of water you consumed makes it seem unlikely that you were dehydrated (1.5 l before starting plus 3 l during), though there is a possibility of hyponatremia. From the Mayo Clinic website -

Hyponatremia occurs when the sodium in your blood is diluted by excess water. Hyponatremia may result from medical conditions that impair excretion of water from your body, or by a significant increase in water consumption, such as by athletes competing in marathons and other high-endurance events.

4:56 p.m. on May 31, 2009 (EDT)
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hmmm, thanks for the information and I think you're probably right on the AMS. I didn't add because I thought it was just me but within a minute of waking up and walking up the steep peak climb my heart beat was racing again (I'd guess about 160bpm), which did at the time seem weird to me, not sure if this adds or not, just reading "Persistent rapid pulse", though my rapid pulse (rapid as in feeling like 150+) did not happen when laying completely still for a while. While I did drink a ton of water I did sweat like a pig and pee 2-3 times while hiking so it doesn't sound like hyponatremia from what I pick up from the wording.

Is altitude sickness something your body can get used to or do you just need better planning? I realize better planning is the smart way to do it, but what can I can more easily fit in a day hike easier than a properly planned acclimated trip.

5:44 p.m. on May 31, 2009 (EDT)
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Altitude sickness is caused, in large part, because there is less oxygen at altitude. If your body isn't used to it, you make up for it by breathing faster. When you breathe faster, your body loses more carbon dioxide (an acid when buffered in your blood). Losing the carbon dioxide puts you into a state of respiratory alkalosis, which just means that your blood pH is not where your body likes it to be. This makes you feel like crap.

People who live at altitude have changes in their blood chemistry which allow them to carry more oxygen.

I seriously doubt you had hyponatremia. You don't get hyponatremic because you drank too much water in one afternoon or even a few days. As long as there's nothing else wrong with you, it takes a while of drinking a lot of water and not eating enough sodium. Pretty much anything you eat these days is loaded with sodium, ESPECIALLY any kind of prepackaged backpacking or outdoors food.

Additionally, at altitude your body loses a lot of water vapor through the lungs, which causes no sodium loss (unlike sweating and peeing). Wheras on a sea level trail most of your water loss is coming from peeing and sweating, on the mountian it's coming mostly from your lungs.

1:01 a.m. on June 2, 2009 (EDT)
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east -

a lot of marathon runners get hyponatremia during the course of a marathon, since some seem to believe that the more water the better. So I have to disagree with your comment on "one afternoon or even a few days".


To expand slightly on east-stingray's comment on altitude, yes, you can acclimatize by following a program that can be summarized (oversimplified, actually) as "climb high, sleep low, and move your sleeping altitude up by an average of 1000 feet a day when above 10,000 feet" People often get in trouble by just what you did - go from sea level to over 10,000 ft in 5 to 10 hours while pushing hard. Some people adjust more rapidly than others (I am lucky enough to be one of those). Others (something like 10% of the population, according to statistics from the top high altitude researchers like Peter Hackett and Charlie Houston (he pronounced it "house-ton")) can not adapt over something like 9000 or 10,000 ft. My Primary Care Physician is an avid outdoorsman and backcountry skier, and is one of those (he had to turn down being expedition doc for an Andean expedition, where they were going to be over 18,000 ft much of the time). Jim S, who posts on here from time to time used to have problems above 10,000 ft, so to do 13kft peaks in the Sierra, he had to camp just below 10,000, then run up to the peak and immediately back down. Since he has been living at a higher altitude in Oregon, he says he can adapt more easily now.

One other thing is that the people most susceptible seem to be males in the 18-30 age range who are physically very fit. Hackett thinks this may be due to men in that age range tending to push very hard, which is something else known to exacerbate AMS.

Best thing is - don't rush it. If you are heading up something over 8000 ft, try to arrange your trip so you sleep at least one night at 7000 or so before doing the hike. If you are going up something higher (say, you get inspired to spend the money to go to Africa and hike Kilimanjaro, which has good trails all the way to the top), then follow the "1000-feet a day" rule (turns out this is hard to do on Kili, since the typical schedule is get to the 15,000 foot high camp in 4 or 5 days, then do the remaining 4500 feet to the summit after getting about 5 hours sleep - which is why something like 50% turn back on the "easiest" route and 20% on the route chosen by more experienced hikers).

10:36 p.m. on June 3, 2009 (EDT)
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Thank you all very much for the comments and information. I feel a lot more informed about AMS and more prepped to avoid and handle it next time! I really appreciate you all taking the time to respond, thank you

April 19, 2018
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