Heart Rate During Pregnancy: Do's and Don'ts

It’s undeniable that exercise is encouraged for moms-to-be with healthy pregnancies. The old guidelines used to specify 140 beats per minute as a heart rate max during pregnancy. We’ve since learned that is unnecessary and new guidelines will suggest moderate-intensity aerobic activity during pregnancy. You may already be aware of this, but what most pregnant people are not aware of is that monitoring heart rate is actually not that helpful during pregnancy. In an age of tracking all fitness moves, your heart rate pre-pregnancy may have been a good indicator of how hard you’re working. However during pregnancy your cardiovascular system changes. Your heart rate, blood volume, and cardiac output all increase during pregnancy. This means that your heart rate may not respond the way it used to. So what are some do’s and don’ts when it comes to heart rate during exercise when you’re pregnant?

DO: be aware if after exercising you’re still feeling out of breath or feel your heart beating fast. Just like before pregnancy, as you recover post exercise your heart rate should return close to your pre-exercise baseline.

DON’T: use a heart rate monitor to determine the aerobic intensity or feel limited by your heart rate during exercise.

DO: aim for moderate intensity, which can be determined by the “talk test” or RPE (ratings of perceived exertion"). During moderate-intensity exercise, you might feel winded, but you should still be able to hold a conversation. Ratings of perceived exertion (overall how hard it feels you’re working) correlate well with heart rate. On a scale of 1-10, you should feel at about 3-4 (moderate to somewhat hard). On the traditional Borg Scale of 6-20, you’d fall at about 12-14.

DON’T: use walks where your heart rate isn’t elevated to count toward your aerobic exercise goals. General physical activity is great and we should all probably move more during the day, but your stroll around the block with your two-year-old, most likely isn’t challenging your heart rate.

DO: discuss if moderate to vigorous exercise is appropriate for you. If you were generally consistent with exercise at higher intensities before pregnancy, your moderate baseline will be different than someone who wasn’t. As we’ve seen with many athletes, your doctor may also say it’s safe for you to work at a higher than moderate intensity.

So now that you understand a bit more about heart rate and exercise, go ahead and get moving. Strength training, walking, swimming, dancing, or the stationary bike are all great prenatal options. If you need a bit more guidance, enjoy this free resource on how to have a strong core during pregnancy.