Used "the other" treadmill at work (the smaller one). The pace and incline that I used yesterday on the "big" treadmill in order to maintain a 140 bpm HR were 7.2 mph and 1%. Today, I had to use 0.5% and 7.0 mph to maintain about the same average HR. [NOTE: subtle differences between treadmills, speed could be a bit off between them, etc. OR, I am more tired from yesterday's 8-miler than I felt. I believe it's the treadmills, because I felt great today. I'll pay attention to this in the future as I switch b/t the 2 treadmills at work.]
Overall, today's 5-miler felt very easy.