Why all the hype about heart rate? Part 1

Getting your heart rate up has become a ‘thing’. Why so much hype over heart rate? Let’s chat about what you need to know about heart rate. We will start by looking at why we use heart rate in the first place.

We use heart rate during exercise because your heart does beat faster as you move. The higher the intensity of that movement, the faster the heart beats. But the truth is, it is not the heart beating faster that makes your heart stronger.

When you do a cardiovascular exercise (aka: Cardio), your heart rate starts to increase to supply more blood to the moving parts of your body.  For the first two minutes of continuous movement, until more oxygen can be sent to them, your muscles use fuel stored right in your muscles to produce energy for muscle contractions. After about two minutes of continuous movement, your muscles can also use oxygen from the blood to create energy. The ‘with oxygen system’ is a more sustainable way to produce energy, so your body will use it whenever possible.

The muscle contractions also help send the blood back to the lungs to replace the used oxygen and then to the heart to be pumped back out to working muscles again. It is actually this greater volume of blood sent back to your heart during cardio that makes your heart stronger over time, not the faster heart beat. This is why your heart rate increasing from things like drinking coffee or getting stressed does not strengthen your heart.  It’s the stronger, not the faster heart beat, that happens specifically with cardiovascular exercise that makes your heart stronger.

When your heart rate goes up during typesexercise that do not involve continuous moment, such as with strength training, you don’t get as much of an increase in the blood returning to the heart as you do with exercises that are continuous.    So getting your heart rate up during a physical activity does not automatically mean you are getting a stronger cardiovascular system.  Your heart is beating faster because you are moving but it might not be beating stronger.   Circuit  training, where you do strength exercises  with some continuous movement between exercises, has been shown to improve both cardiovascular fitness as well as strength, but it does not improve each as effectively as doing strength and cardio separately. 

Continuous movement that is rhythmic and uses large muscle groups is best for making your heart beat stronger, not just faster.  Activities like walking, swimming, dancing, biking, cross country skiing are all great examples of good cardiovascular exercises because they increase the blood flow back to your heart to create a stronger muscle contraction. 

Next in this series on heart rate, we will look at why cardio is about so much more than your heart. 

Keep Moving, Be Well

Janet