Feb. 16, 2000 (Atlanta) -- There are physical and psychological benefits to initiating exercise during pregnancy, according to a report in the January issue of Medicine & Science in Sports & Exercise. Experts say supervised exercise significantly increases aerobic fitness and emotional well-being in previously inactive women, without adverse effects on pregnancy outcomes.
After doctors had characterized the pregnancies as low-risk, researchers randomly assigned 15 inactive women to one of two study groups. Physical measurements were obtained, and body image was evaluated using a standard scale. Additionally, heart rate and blood pressure were monitored before, during, and after a baseline exercise session.
The training program consisted of three one-hour sessions per week for 15 weeks. For the first two weeks, the sessions combined rowing, stationary cycling, and walk-jogging, with a maximum heart rate of 130. Afterward, rhythmic calisthenics, step aerobics, and brisk outdoor walks were introduced, with a maximum heart rate of 156.
After 15 weeks, the exercise group showed significant increases in aerobic fitness and perceived stamina, strength, and energy. But there were no differences in the percentage of deliveries by cesarean section or infant status at birth. For these reasons, the authors say that inactive women with low-risk pregnancies should participate in supervised exercise.
"Many experts urge caution about exercise during pregnancy for women who've been sedentary," says study co-author Arlette Perry, PhD, an associate professor of physiology at the University of Miami. "And others advise against it, because there are no specific guidelines."
"Recent studies have shown that active women tolerate labor better, have fewer episodes of fetal distress, require less medical intervention, and deliver leaner babies," says Perry. "Now, we've demonstrated the safety and effectiveness of supervised exercise during pregnancy in previously inactive women." Doctors say that common sense and safety should moderate exercise workouts.
"Early in pregnancy, physically fit women can usually maintain their workouts," says Michael Lindsay, MD, division director of maternal-fetal medicine and associate professor of obstetrics and gynecology at Emory University in Atlanta, who reviewed the study for WebMD. "But later in pregnancy, aerobics and jogging increase the risk of falls. Throughout pregnancy, the maximum heart rate should never exceed the resting pulse multiplied by two."
"We introduced exercise during the second trimester -- with medical clearance -- to reduce the risk of complications," says Perry. "That means the findings may not be applicable to the general population. Clearly, the data must be replicated with a larger and more representative sample." Perry tells WebMD that she looks forward to conducting more research in this area.
- New research shows that supervised exercise in previously inactive pregnant women improves fitness and emotional well-being, without any adverse effects on the baby.
- Some in the medical community advise against exercise during pregnancy for inactive women, but these findings seem to counter that advice.
- Throughout pregnancy, a woman's maximum heart rate should never exceed her resting heart rate multiplied by two.