I wore my HR monitor today to compare numbers with past experience. The only reason I use it is to keep myself from running too hard, too often. Would that I had known that 25 years ago I might have saved myself from some injuries. My worst injuries were always preceded by extraordinary achievements and over training. I became too fit for my body to withstand, and always broke down.
Anyway, today I averaged 143 BPM for a 9:16 pace. For comparison, the last time I was remotely fit, in 2007 a month after running the Pikes Peak Ascent I was running my 4 mile loop at around 8:50 and 135-140 BPM. So my fitness has a way to go.
By the way, it was warm enough, barely, for shorts and T shirt today. 44 with an east wind, heralding some rain later in the day.