What causes low resting pulse rate?
Patient: Hi,   I am a runner who has had a low resting heart rate for the past few years <60. Since the fall I have started having unexplained shortness of breath which goes away for short periods (x1 week) and then comes back. When I started checking my pulse again it haas been droping below 50 (45-48) coudl this be the cause? Doctor: a low resting heart rate in runners and athletes is due to increased vagal tone which is normal. However the cause for shortness of breath needs to be evaluated. i would suggest1) baseline Ecg2) 2D Echocardiogram3) Chest xray