Posted: Mon Oct 29, 2007 1:43 pm
Hi, Sierra, welcome to the board!
I'm going to take a stab at this and guess that the issues you are having are more blood volume related. The initial responses to ascent to altitude include an increase in hematocrit concentration; however, this is initially less due to increased polycythemia. or red blood cell production, and more due to loss of blood volume brought about by dehydration, due to a number of factors including decreased thirst drive, increased respiration rate (and therefore loss of water through breathing) and an increased diuresis, or urination drive. This loss of blood volume is maintained for the duration of the average backpacker's trip, and is not fully reversed no matter how much you drink ( of course a longer acclimatization is a different story). Once back at sea level, the body will usually get right back to rehydrating in order to reset homeostasis. Therefore, I see the issue as being either 1) you are not rehydrating properly after getting back home and therefore the viscosity of your blood is affecting blood flow and therefore oxygen delivery (if you give blood, they of course tell you to drink lots of fluids, so you have more motivation to drink) or 2) you may be hyperhydrating and diluting your RBC count, which could also affect oxygen delivery. When you exercise, you increase the flow of blood due to increased heart rate and decreased resistance of the blood vessels in the working muscle, so this may explain why you feel good when exercising.
I'm going to take a stab at this and guess that the issues you are having are more blood volume related. The initial responses to ascent to altitude include an increase in hematocrit concentration; however, this is initially less due to increased polycythemia. or red blood cell production, and more due to loss of blood volume brought about by dehydration, due to a number of factors including decreased thirst drive, increased respiration rate (and therefore loss of water through breathing) and an increased diuresis, or urination drive. This loss of blood volume is maintained for the duration of the average backpacker's trip, and is not fully reversed no matter how much you drink ( of course a longer acclimatization is a different story). Once back at sea level, the body will usually get right back to rehydrating in order to reset homeostasis. Therefore, I see the issue as being either 1) you are not rehydrating properly after getting back home and therefore the viscosity of your blood is affecting blood flow and therefore oxygen delivery (if you give blood, they of course tell you to drink lots of fluids, so you have more motivation to drink) or 2) you may be hyperhydrating and diluting your RBC count, which could also affect oxygen delivery. When you exercise, you increase the flow of blood due to increased heart rate and decreased resistance of the blood vessels in the working muscle, so this may explain why you feel good when exercising.