Re: Resting Heart Rate 42 BPM; Good, Bad?
I have the same thing. My RHR gets as low as 40. Since I'm not an elite athlete (I'm 38, lift 3 times a week, do little to no conditioning; bodyweight is 165, SQ 1RM 300) my doc sent me to a specialist cardiologist. Took 3 moths to get an appointment with him (wise old chinese man with degrees from half a dozen US universities). He checked me out and said it's fine. He said they used to think that long distance runners were the only ones with really low resting heart rates, but now they know that sprinters have very low RHR as well.
If you're in good shape, this is a good thing. Like someone else mentioned, the worst thing that can happen is you might stand up too quick and feel faint for a couple seconds.
I think the most extraordinary thing shine I started strength training properly a couple years ago is not that my SQ & DL have nearly doubled, but that my RHR went from 72 to 40-50. And it's not like I was totally out of shape before I began or was over-weight. In fact, I weigh exactly the same (but have lost body fat & gained muscle mass.)
But maybe get your doc or cardiologist to listen to your heart so you have peace of mind.