Black wallnut 

@FrenchFit yup we are closer to agreement than our posts might lead one to believe. I agree that the road to health is a personal one and yours hopefully works for you as mine is working for me.

For the record I take rest days. I also do extremely hard days or a series of tempo days. Health wise I'd probably be better to not do hard days and just make sure I get activity every day. I'll never argue against enough sleep or hydration as I think both play a huge role in fitness and health.