When we periodize our training as endurance athletes, knowing what intensity we are working at is critical to making sure we are doing the right type of training at the right time in relation to our big races or objectives. Keeping intensity low builds our aerobic capacity and fat burning capacity. Exercising at a medium intensity builds our connective tissue strength and muscular endurance. Working hard at lactate threshold or above improves our lactate tolerance and speed. So, how do we know how hard we are working?
For many decades and even today, we have used rating of perceived exertion as a way to measure intensity. We basically defined the efforts as easy, medium, hard, etc. This is how athletes for the better part of the 20th century trained. It works well, especially for an experienced athlete who has plenty of experience exercising at all levels on the intensity spectrum. For most of us, though, when we use perceived exertion as our primary way to measure our intensity, we end up gravitating towards a medium effort in all workouts. A medium effort feels productive. We sweat, we feel like we worked somewhat hard. We didn’t kill ourselves but we didn’t just jog either. The problem is that we never go slow enough to fully develop our aerobic efficiencies and fat burning capacity and we never go hard enough to improve our ability to push lactate. The end result is that we stay fit and healthy but our race performances are always the same – we plateau.
Using a heart rate monitor allows us to have something more empirical than perceived exertion so that we can keep our easy workouts easy and when it’s time to go hard we go really hard and avoid having every workout gravitate towards that medium effort. Heart rate based training has been the gold standard since the early 1990s and still is today. We’ll discuss specific monitors and what training zones are in a future post.
