I ran my 10-mile run on the Distribution canal this morning. My wakeup HR was 51 (49 yesterday), and I didn't have a lot of energy. I was wimpy on the five miles out, but during the five miles back, I had more energy and made it without as many walking breaks as I took on the way out. The shade temperature when I got back was 89. I think the heat we're having is part of my feeling tired during the runs.
My pace is about a minute faster than it was a month ago (high 11 minutes to low 12 minutes, with an occasional spurt into 10+ minutes. This is about the pace I ran last fall when I was working up to 10 miles. I run my "comfortable" pace and don't push speed. My comfortable pace getting faster is another sign that my body is getting stronger since I leveled off my long runs at 15 miles a month ago.
I had a good sleep last night, but my wakeup HR went up a couple of points from yesterday. This is the delay that I've noticed in the past. I lose some sleep and there is a delay before my wakeup HR changes. I get better sleep and there is a delay before my wakeup HR goes down. Usually the delay is 2-3 days.