You are almost old enough to start listening to your body.
Ha ha! My wife agrees with you....she says that I should 'retire' and take it easy. But then I see guys like you, now over 70 and still working. And apparently enjoying the activity...as am I. We both have plenty of time for naps later in life. I feel lucky to still be able to do things. And anyway, I think my body is used to 'going the extra mile.'
Doesn't matter. I take naps when I need them. Which seems more often these days. In fact just thinking about it makes me think I should have one now!
naps are not optional for me. I just hit the wall.
Well I fell into bed at 6pm...and slept soundly for 10 hours. Felt great!