Due to some trouble staying injury free and a swimming background, I have been transitioning from solely running to triathlon. What I noticed when I do my "easy" days on the bike is that I have no trouble keeping my HR in the 130-140 zone (196 max, 177 LTHR). In the past, my "easy" days running have been in the 6:45-7:00 pace range, which is what my college coach had us do. What I have found since I recently began paying attention to my HR is that this pace is usually around 155 for me, which seems a bit high for an "easy" run. I was a decent runner in college, but struggled with overtraining and injuries. I'm beginning to wonder if my easy days have been too fast in the past. Tonight I went for a 6 mile run and focused on keeping my HR between 130-140, which amounted to about a 7:40 pace. I'm struggling to see how running this slow will benefit me. It was a little uncomfortable on my knees as well. Any insight? How slow should my easy days be?