I got a lot more sleep last night, and I felt fine this morning. My wake up HR was 48. I had a nice run, although I was a bit tired at the end; my endurance hasn't fully recovered from Monday night. It's good I took a rest day yesterday and ran today. If I had run yesterday, I would have had a poor run, probably not finishing it, and today would have been a rest day. It pays to rest when one is tired and to run when one feels good.