Right now, I'm a 15yo male (sophomore), and my 5k pr is 19:19. My resting hr is 49bpm, and my max hr is 206bpm. Using the Mcmillan calculator, my easy running pace is 125-175bpm. That calculates to 7:17-8:17 according to the calculator. However, I would more so train to the bpm rather than a specific pace. However, 125-175 is a large range. Is there a more specific heart rate range that I should be targeting for easy runs?