How to Train with a Power Meter vs Heart Rate

By Jiri Kaloc

There are many ways to track performance while cycling. How does using a power meter compare to heart rate or perceived exertion? Let’s explore the advantages and drawbacks of these three popular methods.

Pros and cons of using a power meter

Power meters are the gold standard for prescribing training and tracking performance in cycling. But they aren’t perfect for every scenario. We covered a lot in the previous articles of the series but let’s summarize the main points here.


  • Objective measurement: A power meter provides accurate and objective data about the amount of power you are generating.
  • Consistency: A power meter measures your effort consistently, regardless of external factors such as weather or terrain.


  • Cost: Power meters can be expensive, and may not be affordable for all cyclists.
  • Limited information: Power data alone does not provide information about your body’s response to exercise, such as heart rate or perceived exertion.

The last point hints at why other measuring methods such as heart rate data and perceived exertion may be useful. They both provide valuable context that makes power data more meaningful.

How is measuring via heart rate different?

Heart rate is a lagging indicator of your body’s response to physical exertion. It takes time for the effort to be reflected in changes of your heart rate. Plus, it can be affected by several external factors like the following.

  • Weather and climate
  • Hydration
  • Core temperature
  • Fatigue
  • Stress or excitement
  • Medications
  • Caffeine

Under normal conditions, heart rate responses are predictable and can be very useful even when used alone. However, when used in along with a power meter, heart rate data provide additional insights on the body’s response to the workload. For example, if you see that you can produce more power at the same or lower heart rate, this indicates improved fitness and predicts the potential for improved performance.


  • Affordable: Heart rate monitors are relatively inexpensive, making them accessible to most cyclists.
  • Broad range of uses: Usable in any sport which is handy because power meters are not very common outside of cycling.


  • Delayed response: Heart rate can be slow to respond to changes in effort, which can make it difficult to use as a real-time indicator of performance.
  • External factors: Heart rate is very individual and can be affected by external factors.

Is perceived exertion worth tracking when you use a power meter?

Perceived exertion is a measurement that provides insights into how strenuous a given power output feels. It’s measured on a scale of 0 to 10 and is entirely subjective. This means it’s influenced by external factors, likely even more than heart rate. Just like heart rate, it’s a good way to measure progress. If you feel like 300 watts is easy at the end of a season when it was tough in the beginning, you know you improved. Perceived exertion can also be invaluable in long races. As fatigue builds and conditions change during a race, heart rate and power output become less reliable as measurements of intensity. But you can always rely on how you feel to judge whether you’re pushing past your sustainable pace or not.


  • Free: Perceived exertion is free and accessible to everyone.
  • Holistic measurement: Perceived exertion takes into account everything including physical and mental factors, weather, and nutrition allowing you to always judge how hard you’re working in a given the moment.


  • Subjective and inconsistent: Perceived exertion is subjective and can be influenced by a variety of factors, making it difficult to compare efforts over time.
  • Limited information: Perceived exertion does not provide detailed and accurate information about the physiological response to exercise like heart rate or power output.

Each of the three measurement methods have their place in a cyclist’s arsenal. The more experienced you get as a cyclist, the better you will be at knowing how to combine them. Many cyclists learn to match their perceived exertion to heart rate and power output numbers. But that doesn’t mean either of those become obsolete. If you’re really serious about improving your cycling performance, it’s best to get familiar with all three.