How does Exercise Affect Pregnancy?

Age-old myths made women believe that strenuous exercising during pregnancy can harm the baby. According to a doctor, heavy exercise will not hurt the baby, however, a woman would quickly get tired if she is pregnant.

Bruce K. Young, MD, coauthor of Miscarriage, Medicine & Miracles (Bantam) and professor of obstetrics and gynecology at New York University School of Medicine said that "there is no real evidence that exercise is linked to miscarriage."

Heavy exercise does not have a bad effect on babies inside their mothers. However, a pregnant woman easily gets tired because the amount of blood during the pregnancy increases to about 50 percent. Her heart needs to work harder in pumping all the blood around the body and to an additional organ, the placenta, Parents.com reported.

"That means the stress on your heart will be 50 percent greater for the same exercise that you were doing before pregnancy," Dr. Young says. Women can work just as hard by doing less than what they did before pregnancy.

Pregnancy is not the time for a woman to do heavy exercises, but it is okay and good for them. Cardiovascular exercises can help their heart rate.

In 1985, the recommended heart rate limit is at 140. However, during that time, "the scientific data on strenuous exercise in pregnancy was very scarce," said Dr. Raul Artal, the obstetrician and exercise physiologist who developed the guideline for the American College of Obstetricians and Gynecologists (ACOG), as reported by New York Times.

The recommendation was later withdrawn. "It has no scientific value," Dr. Artal said.

During that time, women were treated as if they had an illness when they are pregnant. They were advised to relax and even simple stretching or bending is prohibited.

"Textbooks, until the late 1960s and early '70s, said pregnancy is not a good time to exercise," Dr. Artal said. "They said, 'It's O.K. to walk.' ''