I heard that you should not exceed 70% of your MHR for your easy runs. When I ran today, my heart rate averaged at 150-155 BPM. My max HR is 200 BPM, so I am running around 75-80% of my MHR. I am training in zone 3 instead of zone 2 for my easy runs, and I have a feeling the reason why I get injured so often is that I am running my easy runs way too fast. Am I running them too fast?