I'm starting my summer off running 4-6 miles every morning @ 6:40-6:50 pace. It's not super easy but I am still pretty relaxed. I can definitely call it a good run @ that pace, at least in my current fitness. In the evening, I run with my buddy who is way more out of shape @ 7:50-8:30 pace, and it feels super easy—almost as if my body is exerting no effort at all.
Am I working my body at all going at this pace? I just notice my watch says I'm burning the same amount of calories:
4.09 miles @ 6:52/mi = 452 Calories
4.06 miles @ 8:29/mi = 445 Calories