Water. Lots of water. If there is one thing you´ll hear again and again , it´s the importance of drinking . A lot.
“I havent peed that much since I was in diapers”
“one litre for every thousand meters..”
Some go on to mention other aspects of fluid balance : thin , clear urine is a good thing , so is a high urine output.
There are some funny aspects , though : this maxim is for one thing never repeated by medically trained .
The end results of altitude sickness are called edema : excess of fluid in the tissues , mainly the brain and lungs. So this is a way of preventing accumulation of fluids in one place , by pouring in more of it in another.
If you find this hard to folllow , join the club.
The basics of fluid balance are exactly this complex : what goes in up here (the mouth) must come out down here (your urinary outlet of choice) . If not , you will bulge in the middle , i.e. the tissues.
There are modifications to this : a minor part comes out via the lungs and feces , and these losses will grow at altitude, but not multiply.
There is a valid observation here , though : some headaches are caused by dehydration , and they will go away when you push fluids. Dehydration is also linked to AMS : loss of appetite is a precursor of nausea. Treating dehydration is good , preventing it is better (keep track of how much you drink , and the color of your urine) but pushing fluids after you´ve cured your headache will not give any better results in preventing AMS.
The fundamental flaw in the water myth though is that you are working against the bodys way of adjusting to altitude : the elevated red blood cell count that takes place the first days are achieved only through concentration – i.e. diminishing blood volume by higher urine output (see myth #2). This is a shift in fluid balance , technically mild dehydration – if you get headache , the mechanism is out of whack and you should treat it.
There is a simple test for dehydration : check pulse after lying down for five minutes , and then again after standing up. Dehydration will givea marked increased in pulse rate. Or just push a litre of fluid. Headache gone : fine , dehydration , now cured. Persisting headache : AMS , stop or descend.
The really fascinating thing about the water myth is the notion of ” the white coats may scoff at us , but we´ve come up with a really great idea.. ” Leaving the medical profession aside , the method has been tried and tested , over oand over again : pilgrims , Silk Route merchants , Gurkha soldiers and many more have struggled to cope with the same problem for more than a thousand years , walking along rivers and sacred lakes and tried everything at hand . If it worked , it would have caught on.