If anyone is not looking at both forums, here is a copy of what I posted on the other one. Gives me something to do in between exercises for my 4.5 months post-total knee and too-slow recovery. Still plan to be in Sierras again this summer. HarveyPost 1
I received an email from Ernie to answer this one. Tough to explain. Incompletely understood. Here is one brief description I found.Edema of Altitude
Peripheral edema and facial edema are relatively common. If seen as an isolated finding without other symptoms of AMS it is not considered AMS, and is not a contraindication to ascent. It is likely to worsen with ascent, and is more common in women than men. It resolves rapidly with descent. Treatment, if necessary, is symptomatic with either acetazolamide or low doses of oral furosemide
This quote was from the NORMAL physiology section of:http://www.high-altitude-medicine.com/AMS-medical.html#edema
I can tell you one story. A friend brought back pictures from his trip to the Himalayas. He was up on the Lhotse Face and turned around at 24,000 ft. His face was incredibly bloated. He did not need to tell me what altitude he was at-it was obvious. Lots of folks look like that up there.
Now why lesser degrees of facial or peripheral edema occurs at moderate altitudes like the Sierras is presumably an individual susceptibility to that particular altitude effect. Other effects, like pulmonary hypertension and risk of HAPE, are likewise highly variable as to what altitude they occur at. Some people get it, some don't.
You can get this edema independent of your salt intake. A healthy body (young, no hypertension, good kidneys) at high workload can handle a lot of salt just fine, extra calories, too. Enjoy it.
As far as dependent edema is concerned (gravity pulling and trapping fluid in lower areas of the body) yes, there may be some of that. But much of it (especially in the face which is near the top of the body, whereas the legs are much lower) is presumably a poorly understood change in membrane permeability. One of the main reasons steroids (like dexamethasone) help altitude and other illnesses is because they are potent membrane stabilizers.
Hope this helps. Post 2
It would be interesting to know how many of us get hand swelling just walking around. Feet we might easily understand just from gravity effect and not-so good veins to return fluids back "uphill" in our bodies. Arms and hands also have different anatomy but the same gravity gradient.
Now for some veterinary medicine. The reason cattle with high altitude illness called Brisket Disease get swelling in the brisket (chest) rather than the legs is that the various connective tissues in their legs are different and tighter than humans and they cannot swell there.
I know one runner who carries a baton with him. I asked him if it was to fend off dogs. He laughed, said yes, that too, but mainly to flip it back and forth from one hand to the other every now and then, first squeezing one hand and then the other. Makes me wonder if the two-walking pole people who get hand swelling get it because they clench both hands in isometric tension, rather than rhymthmic activity. I use a single walking staff and alternate hands. I only do this from long-time habit, but wonder if I accidentally get the same result of avoiding swelling as the baton guy?
Otherwise my earlier post emphasizes the facial edema problem of high altitude. I'm glad the quote I listed gave rosabella some reassurance.