Once in an "extended first aid" class we got the job of measuring eachothers pulserates, and the guy measuring me thought he had failed because he could only find about 30 pulsebeats pr minute, The teacher checked and that was what it was. Something about people practicing strenuous sports developing a more normal pulse rates when exercising and then becoming very slow when just sitting in a class doing no work at all.
While in my 20s & 30s, I did running races, 6 milers, 3 milers, and a couple of marathons. My resting pulse rate was in the 30s. Now I'm 60ish and pulse is like in the 60s too.
The slower the pulse, in general, the healthier you are. 
JakobA the unAmerican. 