My heart rate this morning was 44. I checked it three times to be sure that number wasn't a fluke. This is the first time in about 25 years that my heart rate has been that low. During my marathon training in the early 80s, my HR was 44. One day it went to 40 and stayed there during the rest of my marathon training. During the past couple of years, my heart rate went to 45 once, and it has been 46 quite a few times. I consider 47-48 as my current "normal" rate. During the past couple of weeks it has been 51 with one excursion to 55. It will be interesting to see what my HR is tomorrow. I've been sleeping well this past week. I often mention my sleep in this blog, because a lack of sleep is my most common cause of a high heart rate.