Thanks for all the replies. Here's a little more info. I'm 48 years old and have been training for about 12 years. I'm not overweight. I sleep 6-8 hrs a night. In a normal day I drink at least a gallon of water a day, more on days I train. I don't do any other work out except tkd and I do that two or three days a week for two to three hours at a time. Some of those nights I am teaching so the workout is less intense. I haven't had a good blow too the head in quite some time though I probably deserve one. I don't drink alcohol or do drugs any more and I am on no medication. I eat a high protein, low fat, high fiber, fruit and vegetable filled diet. My blood pressure is within normal range. I don't eat before class (mostly because of the beans!). I did mention it to my MD and he said drink more water, but I don't think I can drink more, I drink a lot already. I think I'll see about getting a second opinion from a doc with more experience with sports.
Jim