Hi, My doctor wants me to donate 2 units of blood for my surgery, the problem is that when I go to do that, my pulse is way too high. I went on Friday, and it went from 107 to 113, and they wouldn't take my blood. I went back today and it started out at 109 but went down to 103, the range is 50-100, the tec. finally fudged on the form and put down 100. So I have one unit saved. I took my blood pressure medicine before I went, does anyone have any insight into what can be causing this?