Well, Polycythemia Vera is one possibility, but so is dehydration. If you're only drinking 3 cups of coffee + some tea per day, you probably are dehydrated, particularly in hot weather. During the summer, you should be drinking a big glass of water when you get up in the morning, because you dehydrate a lot during the night. After that, there are no hard and fast rules, but for the purposes of this blood test, I would suggest drinking 8 ounces (1 cup) of water per hour before you go in for your blood draw. If your H&H readings are still very high, then your doctor might want to refer you to a Hematologist for further studies. Polycythemia is not a trivial disorder, so if you have it, you need to know about it to prevent complications.
Well, to clarify the previous answer. Caffeine is not a diuretic by definition. Diuretics deplete the body of sodium, whereas caffeine inhibits the enzyme phosphodiesterase. It gets more complicated, but it's not a true diuretic. Second what else do you do, how old are you, what are you eating? Erythropoetin stimulates the formation of new RBC's. What was your RBC count? Hematocrit is the percentage of RBC's per volume of blood, so it sounds like you probably have a lot of RBC's as well. Blood cells can circulate for 120 days before being filtered predominantly by the spleen and liver. So, taking that into account, you might increase intake of water and wait a few months. Good luck
coffee and tea are diuretics. Try drinking smart water or regular water, 8 glasses a day. you can still drink coffee and tea but drink more water than either of them. you can damage multiple organs if you are not fully hydrated.