You’ve been training for years with heart rate and you’ve been successful. You have reached your goals and been confident in your training plans. So why would you want to start training with power? What is all the fuss about power meters? And why should you put it at the top of your holiday gift list?
To get ready for any competitive event you must train. In order to train precisely for a given event you must know exactly what the demands of the event might be. With a power meter you can do just that. You can replicate the demands of an event from BOTH a duration and intensity perspective. Power meters reflect the amount of work you are doing at a given moment. Heart rate in contrast does not.
So what to I mean by that? For example, when you are climbing a hill your heart rate climbs steadily but likely your speed and power remain constant. When you crest the top and start descending; your power plummets while you heart rate lags behind. It can even increase for a bit before you start your descent. That is not an accurate picture of the work you are doing. Make sense? Power reacts rights away; there are no lags in its reaction.
Power is a direct reflection of performance while heart rate is a reflection of what an athlete is experiencing at a given time. Heart tells us more about our effort rather than our performance. And this is the fundamental difference between the two measures. Performance is what is rewarded in racing, not effort.
Heart rate also fluctuates due to many other factors, not just the work you are doing on your bike. Heart rate is affected by temperature, hydration and how recovered you are from a previous effort and sometimes illness (either before or after).
So once you get that power meter for the holidays, should you throw out your heart rate monitor? Absolutely NOT! You can use both measures together to gain more insight into your aerobic fitness. For example, as you continue to train your aerobic engine, you will begin to notice the relationship between heart and power. This is especially important in the base phase of training. As you train with a power meter over the course of time, hopefully you will notice that your output, or power, climbs while your effort (heart rate) stays lower. You mays be riding in heart rate zone 2, but your power reflects level 3. This tells you that your fitness in increasing. And that, my friends, is exactly what we want to know.