Question
I exercise frequently and also teach water aerobics. Now that I'm pregnant, I've been told that I shouldn't let my heart rate go over 140 beats per minute (bpm). What happens to me or my baby if my heart rate exceeds 140 bpm?
Answer
If you exercised regularly before your pregnancy, you shouldn't be too concerned about exercise during pregnancy.
In 1983, the American College of Obstetricians and Gynecologists (ACOG) originally set a guideline of no more than 140 beats per minute during exercise as a recommendation for most pregnant women. This was based on limited research that suggested higher heart rates during pregnancy may slow the growth of your baby in the womb. But further research found this only occurred in women who exercised too much and didn't consume enough calories. So exercise alone wasn't the primary problem.
ACOG now recommends 30 minutes of exercise a day for pregnant women, but doesn't make a heart rate recommendation. Doctors now recognize that every woman has a different fitness level and no recommendation could account for those differences.
When you exercise, ACOG recommends that you should be able to carry on a conversation comfortably during your workout. If you're already physically fit, you may be able to make only a few changes to your workout to accommodate your pregnancy. You should talk to your doctor before continuing your current exercise routine.
Last Updated: 08/02/2007
