Feeling tired

I felt tired all last week, but I was able to complete my runs and feel fine. I felt tired this morning, my wakeup HR was 53, so I decided to do a rest run of 4.2 miles instead of my normal 6.4 miles. If I continue to feel tired this week I'll continue to do rest runs. I've had good running this past month, and I'm not surprised my body needs a rest. I remember reading many years ago an article by a world-class runner who recommended a rest week each month.