Should I keep my heart rate no higher than 140 beats per minute when exercising? 

One of my pregnant patients recently asked me if she should keep her heart rate no higher than 140 beats per minute when exercising?

Answer:
There is presently no scientific basis and no official recommendation to keep the heart rate during pregnancy below certain levels.

Physical activity during pregnancy has benefits beyond maintaining or improving physical fitness, including helping with weight management, reducing the risk of gestational diabetes and preeclampsia, making it easier to cope with labor pain and easing recovery from childbirth.

ACOG, the American College of Obstetrics and Gynecology encourages pregnant women to engage in moderate-intensity exercise for at least 20 to 30 minutes a day most days of the week, as long as there are no medical or obstetric complications.  No upper level of safe exercise intensity has been established. Women who exercised regularly before pregnancy and have no pregnancy-related complications can engage in high-intensity exercise programs, such as jogging and aerobics, with no adverse effects.

Some modification of exercise routines may be necessary to accommodate physiologic and anatomic changes that occur during pregnancy, such as changes in the center of gravity, laxity of joints and ligaments and respiratory changes. Activities that involve a high risk of injury, such as downhill skiing and horseback riding, should be avoided, as should contact sports, scuba diving, skydiving and hot yoga.

What forms of exercise are safe during pregnancy?
Certain sports are safe during pregnancy, even for beginners:

  • Walking is a good exercise for anyone.
  • Swimming is great for your body because it works so many muscles.
  • Cycling provides a good aerobic workout.
  • Aerobics is a good way to keep your heart and lungs strong.
  • If you were a runner before you became pregnant, you often can keep running during pregnancy, although you may have to modify your routine.