What Are the Specific Benefits of Exercise?

Pregnancy

Healthy women with normal pregnancies should exercise at least three times a week, being careful to warm up, cool down, and drink plenty of liquids. Many prenatal calisthenics programs are available. Experts advise, in general, that when exercising, the expectant mother's pulse rate should not exceed 70% to 75% of the maximum heart rate or more than 150 beats per minute. Fit women who have exercised regularly before pregnancy, however, may work out more intensively as long as no discomfort occurs.
According to a new study, vigorous exercise may improve the chances for a timely delivery. Overly strenuous exercise during pregnancy is not advocated, however, for women who did not exercise intensely before becoming pregnant. And all pregnant women should avoid high-impact, jerky, and jarring exercises, such as aerobic dancing, which can weaken the pelvic floor muscles that support the uterus. During exercise, women should monitor their temperature to avoid overheating -- a side effect that can damage the fetus. (No pregnant women should use hot tubs or steam baths, which can cause fetal damage and miscarriage.)
Swimming may be the best option for most pregnant women. It involves no impact, overheating is unlikely, and swimming face down promotes optimum blood flow to the uterus. Walking is also highly beneficial. To strengthen pelvic muscles, women should perform Kegel exercises at least 6 times a day, which involve contracting the muscles around the vagina and urethra for 3 seconds 12 to 15 times in a row.