How Beta Blockers Affect Your Target Heart Rate

If you have high blood pressure, treatment often requires medication with a beta blocker, a common type of blood pressure medication that lowers your resting heart rate. Exercising regularly, another important component of managing high blood pressure, also lowers your resting heart rate. Hence, if you take a beta blocker, you will need to make some adjustments when calculating your target heart rate while doing aerobic exercise.

How Beta Blockers Lower Blood Pressure

Beta-blockers work by blocking the effect of epinephrine (adrenaline) on the tissues—specifically, by blocking the “beta receptors” that bind epinephrine.

Among other things, blocking the beta receptors slows the heart rate, reduces the force of contraction of the heart muscle, reduces the amount of oxygen the heart muscle needs to do its work, reduces stress on the vascular system, and tends to lower the blood pressure.

How Exercise Reduces Your Resting Heart Rate

Regular aerobic exercise lowers your resting heart rate. When you do aerobic exercise, you have an increase in blood flow to your muscles, as well as an increase in the volume of blood returning to the heart.

Over time, the left ventricle adapts and enlarges to accommodate the increased volume. This larger cavity can hold more blood, and ejects more blood per beat, even at rest; your resting heart rate drops because each beat delivers a bigger burst of blood, and fewer beats are needed.

Calculating Your Target Heart Rate

Your maximum heart rate—the upper limit of what your cardiovascular system can handle during physical activity—can be estimated by subtracting your age from 220. So, if you're 35 years old, your estimated maximum heart rate is around 185 beats per minute (bpm).

To determine your resting heart rate, and monitor it during exercise, you can use a heart rate monitor or take your pulse on the inside of your wrist by counting the number of beats per minute.

It is recommended that you exercise within 55% to 85% of your maximum heart rate for at least 20 to 30 minutes to get the best results from aerobic exercise. In the example of the 35-year-old above, the target heart rate zone would be from 102 to 157 bpm.

Beta-blockers can slow down your heart rate, but their effect isn't necessarily exactly the same for everyone. For some people, it may only slow the heart rate slightly, while the effect can be more pronounced for some people.

Your target heart rate during exercise might be different if you are using a beta-blocker. Factors such as your age, your heart condition, and your overall health can affect the rate that you should aim for. And for many people, reaching a specific target heart rate isn't a major consideration in their exercise routine. Talk to your doctor about what your goals should be when it comes to exercise.

Adjusting Your Exercise Goals

If you’ve had an exercise stress test while on beta-blockers, the results will provide numbers describing your exercise capacity. These numbers should be your guide when planning your exercise goals.

Using a System of Perceived Activity

If you prefer, you can also use a system of perceived activity to help determine your target exercise level. This system essentially works by having you rate how tired you feel during a given activity, on a scale from six (resting) to 20 (maximum effort).

If you’re exercising, how difficult does it feel? The more tired you feel, the higher the rating. It will take some experimenting to develop your personal rating scale. Once you have a rough scale in place, your target range corresponds to a rating of about 12 to 14.

A Word From Verywell

If you’re new to exercise, remember to check with your healthcare professional prior to beginning an exercise program to make sure your heart can keep up with what you have planned. They may have some suggestions to help you ease into a new exercise program safely.