Should You Run or Walk to Your Baby-Making Goals?

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Are you the right weight and trying to get pregnant? If so, you may want to skip the spin classes...

The Scoop

For women already at a healthy weight, strenuous workouts could do more harm than good when it comes to how long it takes to get pregnant. And for overweight women? The exact opposite might be true, according to a study on exercise, fertility, and body shape from Boston University.

How much exercise is too much? Comparing self-reported exercise habits among more than 3,600 women actively trying to conceive, researchers found that healthy weight women who exercised vigorously—running, fast cycling, swimming, aerobics classes—for five or more hours per week had a 42 percent reduced likelihood of becoming pregnant compared to those who did lighter exercise or none at all, reports HealthDay.

On the other hand, when overweight women in the study took part in these same types of strenuous workouts, their odds of becoming pregnant in any given month actually increased.

Whether it worked for or against a woman's fertility, researchers were not expecting to see such a dramatic impact from five hours per week of hard exercise. "We were surprised to find that even relatively small amounts of vigorous activity seemed to impact fertility," says researcher Lauren A. Wise, an associate professor of epidemiology at the Boston University School of Public Health (via WebMD).

Your Fertility

If all this leaves you feeling confused about how much exercise is good for your preconception health, consider what else BU researchers uncovered: moderate exercise seems to be a fertility booster for all women, regardless of body type. This means that if you are overweight and haven't worked out much lately, you don't need to become a gym rat in order to reap some benefits of exercise—a brisk walk several times a week may still be enough to boost your fertility.

And for healthy weight women accustomed to grueling workout routines, you probably don't need to cancel your fitness club membership—just dial down those high-intensity workouts to moderate physical activity and your baby-making plans will likely stay right on track.