I was just prescribed to take Vyvanse for my ADD so that I can perform better academically in college. However I'm also a serious cross country and track runner and have been reading up on the side effects of it and am very concerned. People have mentioned increased heart rate, out of breathe, fatigue, etc. I know that these are possible worst case scenrios, but are these common side effects for competitive runners who take Vyvanse? And if I stopped taking it, could I even experience withdrawal effects?