In 2011, an elite runner made headlines for running the Chicago marathon.

That fact alone is not noteworthy, but the fact that she gave birth to a full-term baby later that same day was.

While lots of opinions flew back and forth about whether the achievement was healthy, physicians say exercise during pregnancy can help women who have healthy pregnancies feel even better.

Exercise improves circulation, which in turn helps prevent constipation, hemorrhoids, leg cramps and swelling. Exercise also releases endorphins and helps you sleep better. Workouts also can strengthen your back muscles, helping to prevent lower back pain that comes with carrying an extra 20 pounds in front of you.

But don’t get trapped into an all-or-nothing approach to exercise. Make sure you run your workout regimen past your doctor, who may suggest keeping the exercise to moderate activity such as walking, swimming and cycling on a stationary bike, especially if you don’t typically exercise at a high intensity.

Those who were runners before pregnancy can still test the jogging waters when they become pregnant, as long as the pregnancy is healthy and low-risk … and as long as your doctor gives it the OK.

Moms-to-be should avoid exercises that require you to lie on your back as your tummy grows. The weight of the placenta slows the flow of blood to your heart, and in turn the blood flow to the fetus. Also, avoid sports that could wind up injuring you, such as basketball, skiing on both water and snow, and horseback riding.

Otherwise, pregnancy is a fine time to get moving — but listen to the demands of your body, allow yourself time to rest and don’t expect to run marathons. After a few short months, you’ll be running a different kind of marathon.