So you’re all hopped up on fitness and you’re looking for a way to take your workout to the next level. You’ve heard that running at a higher heart rate can help you burn more calories and get in better shape, or want to participate in a marathon to see how far you can push yourself. Surely, running at 90% of your max heart rate can land you a respectable finish in a marathon or count as an awesome day in the gym. But how long can you keep it up? Don’t be anxious, as it turns out a regular … Continue reading How Long Can You Run At 90 Max Heart Rate