What should the pulse rate of a 73 year old male be?

For most people a resting heart rate of 57 is fine. Medical guidelines put "normal" resting pulse (heart) rates at 60-100 BPM. 3 points off is nothing to worry about. Young, healthy, athletic individuals tend to have lower resting heart rates, than other folks. Some medications, such as digitalis, will slow the heart rate. People on medications used to specifically slow the heart rate usually use "60" as a cut off for holding such medicines.