Some experts believe that power meters and speed and distance devices have made heart rate monitors irrelevant.
Heart rate monitors took the endurance sports world by storm in the early 1990s. The practice of heart rate monitoring appealed to cyclists, runners and triathletes as a way to make their training more precise and scientific.
By the late 1990s, a majority of cyclists and triathletes (if not the majority of runners, who always lag behind in terms of adopting new technologies) used heart rate monitors in every workout and race, heart rate-based training systems dominated systems based on other intensity metrics, and coaches such as Sally Edwards had made healthy careers as heart rate training gurus.
But then the backlash began. Skeptical coaches and exercise scientists pointed to the limitations of heart rate monitoring and the dangers of over-relying on it. With the advent of power meters for cycling, some coaches and experts began to argue that proper use of a power meter makes heart rate monitoring pointless. And with the advent of run speed and distance devices, the same argument is now being made to runners.
My position is not quite so extreme. I believe that there is potential value in heart rate monitoring, but that heart rate should be used as an intensity metric secondary to power or pace. First let me make the case against heart rate monitoring, then the case for it, and then let you decide what to do.