Now I can be like those cyclists that post charts of watts, HR, distance, elevation, etc., etc... This is a heart rate plot against time for a 7x400 workout totaling 4 miles. After a 1 mile warmup, I ran 400 and walked/jogged 200 seven times. The long rest between laps 4 and 5 was a water break. I'm not sure how accurate the HR monitor is, since my maximum is supposed to be 185. What happens when you go over??
Here are my 400 splits: