Did my interval session this morning. 3, 6, 9 and 12 miles. Times were 8:40, 17:55, 24:03 and 34:12 compared to 9:40, 16:42, 26:43 & 34:17 a month ago. Terrain was similar but not identical which accounts for some of the differences, not sure about wind conditions (none today). I could not get my HR over 155 the whole ride. I pushed as hard as I could and way harder than I did Sunday, but could not get the HR up. Sunday I don't think I would have had a problem hitting 160 - 165 and even had to keep curtailing my effort to keep it down.