My wife and I drove to the local gym, and she ran her mile + 1 lap while I ran and walked the indoor track for 40 minutes. I had hoped I could last for 60 minutes, but I could tell I was getting tired, so I stopped. My wakeup heart rate was 54, which is the lowest it has been for several months. However, I only had 4 hours sleep Saturday night, and that lack of sleep got to me after 40 minutes.
I have an anxiety problem that causes me to not sleep very well when I have something important scheduled for early in the morning. My son-in-law came down from Evanston, WY, on Saturday evening, and I drove him to the Salt Lake airport Sunday morning; we left home at 7 am. I slept well the night before until about 4:30, and then I woke up and didn't go back to sleep. Last night (Sunday night) I slept very well, and that, I'm sure, contributed to my low wakeup heart rate this morning.