I have been taking Topamax for 3 years now. I can definately say that Topamax has had an impact on my stamina. I truely don't know why, though. I wish someone could explain it to me. I guess with the drug you are less likely to sweat and get overheated. But, if you are in good shape that should not account for the kind of fatigue I have experienced. I really think it is more than that. It feels like to me that there is a blood pressure issue when you are running and doing vigourous cardiovascular excercise. It feels as if there is not enough oxygen getting to your all of your vital organs or something. It also feels as if you are totally out of shape and cannot take even one deep breath for several minutes. Hills are nearly impossible for me these days. But, I am a serious runner. I run about
70K a week. I cannot catch my breath. I am always winded. It is more than needing a little water and being over heated. I know this because I have used to run in the desert everyday. I was constantly needing a little water and overheated. I really didn't feel like that. It was a very different feeling. This feeling is a tightness in my chest and throat. Almost as if you have a chest cold.
There was a period of four months, however, when I wasn't taking the drug. I was running faster and I had so much stamina. The problem was that I had migraines. The good news was that my lungs and cardiovascular system was not actually out of shape because within days of discontinuing the drug I noticed a huge difference in my stamina. Unfortunately, however, when I started taking the drug again the problem returned immediately. So, again I think it has to be the way that the blood carries the oxygen to the lungs or something like that. Maybe not it just seems that way to me. It seems that would be the only way that the lungs could respond so quickly once I discontinued the medication over the summer and then reacted so negatively again when I started taking the medicine again. I obviously am no doctor here I am just saying how the medicine impacts my ability to excercise.
I obviously am also still taking the drug so the benefits for me are still there. I wish I didn't need anything but noone is perfect I suppose. My only advice about the drug is to start very slowly and maybe you will not notice how it slows you down.
The other thing is the dosage that you take. I take a higher than normal dose. At a lower dose, you may not be as bothered by the side effects. Good luck! Hope that helps!