ve been running all my life (now 59), and typical resting heart rate
is around 45-55 bpm. Sleep will lower it somewhat, so a waking heart rate
in the forties is not a surprise. The reason for a slow rate given to me by physicians and cardios is that an athlete's heart will have enlarged a bit with the constant exercise, and with an enlarged capacity, less pumping is needed for normal activity. Hey, that blood pressure is awesome.