Hi ickle kitty,
Elevated blood viscosity means that your blood is stickier than what is considered to be within the normal range. It isnt actually related to our EDS as afar as I know.
Healthy blood is usually low viscosity which allows the blood to flow freely. Your blood viscosity can be affected by fluid intake, diet (ie high fat/cholrestrol diet). The stickier the blood the more likely that you get fat deposits building up in your arteries etc. A high percentage of fat in your blood can also make red cells stick together reducing the oxygen available in the blood, so this may have 'some' affect on feeling a bit dizzy and drowsy especially after eating heavy meanls. It can also lead to angina pains or other cardiac symptoms.
Stress can also affect blood viscosity and continued stress wont help either. I have looked this up for you and apparently if your diet is high in fat, chlorestrol, refined carbohydrates and animal protein, you can help almost detox by reducing all these foods and within a few days it can have a marked improvement on the viscosity.
I had elevated blood viscosity once and it was apparently due to lack of fluids, I havent had any problems since as far as I know, altho I do have the type of cholrestrol problems that your own body makes rather than what you eat, but I am guessing this could be a problem for me now.
When do you have to go back fro some more blood tests? in the meantime try increasing fluid intake, decreasing fat, chlorestrol and animal protein in your diet and see if that makes any difference.
Hope this helps.