I didn't sleep very well Sunday night, due to an upset stomach, and my body was tired and my wakeup pulse rate was high Monday morning. I did run on Monday, but I only ran 2 miles. I also came down with a cold on Monday. My nose was drippy for three days, and my energy level was low, so I didn't run on Wednesday or Thursday. My nose quit dripping on Thursday, but my wakeup heart rate was high on Thursday, Friday, and today. I didn't run today, but my wife and I did walk for 0.6 miles. I've been sleeping well this week, and my wakeup heart rate should start to drop in the next few days. Whether I feel fine or not on Monday will determine whether I run then or not. When I was younger, I could run through colds, but now I usually don't run through colds because my energy level is usually low during a cold.
My cold this week was the first cold I've had in over a year. I think this cold was brought on by my body being tired and my not getting much sleep Sunday night. Colds are a sign that one's immunity is low.