Just as it was getting dark, I ran for an hour on the Jordan River Parkway. I didn't run in the morning, as I usually do, because my wife and I took three grandchildren to the South Towne Mall to ride the carousel and the escalator and to have lunch at Wendy's. My pace during the run was a comfortable pace around 12:10. It was dark on the way back, but because the sky was overcast, the clouds reflected light from the city, and I could see the trail as if it were dusk instead of dark.
My wakeup HR was 49, and I felt fine during the day and the run.