Progression-increased effort the last 4 miles. 1st run with my new HR strap, and my HR didn't go as high as I thought, but I'll have to figure my new max at this age. The last time I checked I was several years younger. Very humid. Interrupted sleep last night with the old dog, etc. I felt like going for the full 14 Coach Neely planned but the heat (in the 70's) & humidity took its toll and by the end, was glad to get 12.