Do you guys follow your heart rate when training? I've had my heart rate monitor with me this week when I've gone cross country skiing and my average heart rate for two hours has been a bit over 170. I think my max heart rate is around 205-210 and base heart rate around 50. Last summer I cycled for about 20 hours straight and during that my average heart rate was around 150. I think most endurance athletes recommend something like 120, but it obviously depends on the person. I've heard high heart rate training might lead to overtraining and overall not being as effective as lower bpm training. Any truth to this? I've never really had problems recovering and I felt great even after that 20 hour cycling competition.