The Importance of Heart Rate Training

A 10 minute interval is going to be your minimum effective duration at about 95 to 100% of FTP. It takes three minutes for your heart rate to catch up, so your heart rates, your heart supplying the oxygen. So this kind of creates like a minimum effective duration for FTP. If you do one by 25 minutes, you now have five minutes less work to do. You're going to have a workout that's just as effective.