What Are Heart Rate And Power?

Heart rate and power are commonly discussed values when talking to cyclists. If you are unsure what the numbers mean, this article is for you. Keep reading to gain an understanding of what your heart rate or power number is telling you.

Heart Rate

Heart rate is a measure of how many times your heart beats in one minute. I’m going to describe how a gasoline car works to give you a better understanding of why your heart rate increases as you exercise.

When you press on the gas pedal, gas is pumped from the gas tank to the engine. The engine uses the gas to create mechanical energy via combustion.

If you press harder on the gas pedal, more gas is delivered to the engine. This larger volume of gas allows your car to create more energy. The result, you speed up.

Your body works in a very similar way while performing aerobic activities like long distance cycling or running. Instead of using gas to create energy, your body uses oxygen.

Your heart pumps oxygen-rich blood from your lungs to your muscles. Your muscles accept oxygen from the blood and use it to create energy.

If you want to accelerate from a walk to a run, your body needs more oxygen to produce enough energy. Your body does two things to get more oxygen. First, you breathe faster which brings more oxygen into your body. Second, your heart beats faster delivering more oxygen-rich blood to your muscles.

The critical thing to note is your heart beats faster as the intensity of exercise increases. This means, your heart rate is directly related to how hard you are working.


Heart rate tells you how hard your body is working, but it doesn’t tell you about the intensity of the exercise. Here is an example.

If your heart is beating at 120 beats per minute while performing squats, you have a clear picture of how hard your body is working. What your heart rate doesn’t tell you, is how much weight you are lifting.

When it comes to cycling, a power meter more or less measures how hard you are pedaling. I say more or less because I’m simplifying the definition for the sake of explanation.

If I’m being specific, the equation for power is as follows:

Power = Torque x Cadence

Since torque calculated using force, you can increase your power by pressing harder on the pedals or by pedaling faster. Your power meter reports your power on your bike computer as a number of watts.

Again, if you want an easy way to think of power, remember it is related to how hard you are pedaling.

It’s That Simple

So there you have it. Power measures how hard you are pedaling. Heart rate tells you how hard your body is working to create the power. To learn about how you can use heart rate or power to improve your training, read: How Are Heart Rate And Power Used For Training?

I hope this article helped. The next time you are on your group ride, you won’t have to smile and nod when someone brings up power or heart rate.