Originally Posted by
revchuck
It's definitely beneficial. When doing intervals, you do them within a specific percentage range of your functional threshold power (FTP) based on what you're trying to accomplish. It's far more accurate than HR, especially for shorter, harder intervals where HR doesn't have time to react. Also, lots of things can influence your HR that wouldn't influence your power - watts are watts, doesn't matter if you're sick, dehydrated or stressed.