Exercise During Pregnancy: How Little is Too Little And How Much is Too Much?

The U.S. Department of Health and Human Services has released guidelines on physical activity for pregnant women. They advise that healthy, pregnant women may perform moderately intense exercise for at least 150 minutes weekly. Women who exercise vigorously are encouraged to continue doing so as long as they remain in good health. Non-exercising women may begin to do aerobic exercise when pregnant.

Historically, obstetricians have been hesitant to advise non-exercisers to become active and many have recommended that women tame the vigor of their exercise regimens with pregnancy. It is assumed that these cautions are attributed to the lack of evidence regarding safety of exercise in pregnancy.

Recently a study was undertaken to evaluate fetal well-being in women with otherwise healthy pregnancies (low-risk). Women studied included those who exercised < 60 minutes weekly, > 60 minutes weekly and those who described themselves as “highly active” exercising > 4 days weekly.  These three categories of women were then subjected to aerobic exercise and their aerobic capacity was monitored as well as was the fetal response in utero. Although there was transient increase in fetal heart rates mirroring the increases in the maternal heart rate with exercise; no immediate or long term adverse effects were noted.

Healthy mothers make healthy children. The benefits of exercise extend to the mother and fetus alike. Women, in conjunction with approval from their obstetricians, should be comfortable following established guidelines.