How the flock do you guys have such low rates?
We are born that way.
I saw an ECG done on my (non-athlete) mother when she was in her late teens. Her heart rate was below 50.
Oh well.
It really is luck of the draw, I think. It's probably true that most who are drawn to athletic hobbies are relatively naturally suited to them, and have hearts that can shovel a lot of highly oxygenated blood reasonably efficiently. But not all, of course. I'm sure that a comprehensive study will find some exceptional athletes who have relatively high resting HRs but can still deliver the requisite amount of good stuff to the appropriate parts of the body at the right time. But it would also have to be true that, without the training they'd need to be good at what they do, their heart rates would be a lot higher.