I just started on 12.5 mg of atenolol three days ago. Within one hour of taking the first dose, my pots was eliminated. The only bothersome thing is that it sometimes makes me feel very sleepy, but it seems like I can counteract that with a cup of coffee. Today is my third day, and I seem to have more energy. It could be just one of those better days and a coincidence. But maybe a lot of my fatigue was caused by my heart running too fast all of the time. Has anyone had anyone good success with atenolol for the fatigue/exercise intolerance/post exertional malaise?