I have understood that resting HR is highly individual as is max HR. I have a very low resting HR as does my brother and I'm only in moderate shape. My max HR is also quite low for my age (I'd like to believe it's 195 but 190 is probably more accurate and I'm 24. Cycling max is atm 180)
I'm quite tall so I think that might have something do with heart rates. My resting HR is 43