I felt fine on Saturday after my run and throughout the day. But, around 10 pm I could tell I was coming down with a cold. Not just a regular cold, but one that sapped my strength. Even though I woke up every hour during the night, I managed to get 8 hours sleep. I got an additional 4 hours in naps during the day on Sunday. I didn't have a lot of energy on Sunday and just rested and napped. By Sunday night I could tell my cold was going away.
This morning, my wakeup HR was about 15% high (53), but I had a lot more energy than I had on Sunday. I'm taking a rest day today and may take one tomorrow, depending on my wakeup HR and how I feel.
I don't get many colds, so when I do get one, I try to figure out why. Part of it is that my son, daughter-in-law, and grandson have had colds this past week. Since they live with us, I've had a lot of exposure to their colds. The other factor is that when I ran the GSL, I really pushed myself hard, harder than I've ever pushed in a race. I was really tired after the race, but I seemed to recover fine. Running an hour and 20 minutes on Saturday may have been too much. I seemed to handle the hour on Wednesday, but that extra 20 minutes might have pushed me over the edge, so to speak.