I had surgery a few weeks ago and my resting heart rate has gone from the 60s and 50s to 80 and 90s. When I stand up I am short of breath and start getting dizzy after a few minutes. I have never felt this exhausted.....anemia? What else could it be to cause this change?
Firstly what kind of surgery, and other Co morbidity, that will give me a clear idea of the possible reasons, and they can be varied, and just random naming would cause undue anxiety.  As you think anemia, some infection may lead to the symptoms you describe.  Many a time if it was a major surgery, the recovery itself till your tissue self-heal may lead to generalized body weakness which may recover by 2-3 weeks.  Regards Chat Doctor. Chat Doctor .com/doctors/