Is your workout routine affecting your chances of getting pregnant?

Exercise can be great for your dating life (hello, hot sweaty dude on bike 12). And its benefits, like increased energy, core strength, and flexibility, can definitely boost your sex life, too.

So we were surprised to hear from a physician that exercise—the full-throttle variety, in particular—may also affect your ability to get pregnant, although it depends on a variety of factors (like your weight, for instance) and only applies to the short-term.

Here’s what you need to know, whether you’re trying to have a baby now, or are actively trying not to, but plan on taking the step many years down the road.

The basic facts

David Reichman, MD, who specializes in reproductive medicine and helping women get pregnant, says consistent, vigorous exercise—like cycling or running four or five hours per week—can lower your chances of getting pregnant if you’re currently at a healthy body weight. (Exercising while overweight has actually been shown to have the opposite affect, improving your chances of getting pregnant.)

A study of competitive female athletes, for example, who did five hours of vigorous exercise per week (including running and fast cycling) had a decreased likelihood of getting pregnant (versus those who were only working out moderately, such as brisk walking or leisurely cycling).

Why would your healthy workout habits get in the way of your reproductive health?

The chemistry

Dr. Reichman says it’s all about messages that your brain can’t send while you’re busy sweating.

“Consistent, highly vigorous exercise has the potential to affect your ability to get pregnant, because the efforts of the corpus luteum (what’s left of the follicle after a woman ovulates) are disrupted by not receiving its usual input from the brain,” Dr. Reichman explains. The corpus luteum, just FYI, produces progesterone, a hormone necessary for supporting pregnancy.

“The brain can be thought of as providing a life-line for the corpus luteum; if exercise disrupts that life-line, the health of the corpus luteum can be jeopardized.”

What this means for you

So, do your tri-weekly spin and barre classes have long-term effects on your baby-making ability? No, Dr. Reichman emphasizes.

“If someone wants to be SoulCycle junkie and go twice a day, it will only affect their fertility temporarily in those months,” Dr. Reichman says (and reiterates that this only applies to you if you’re maintaining a healthy body weight.)

So, if you are trying to have a baby, he suggests you cut down on intense, sweat-dripping workouts while you’re trying to conceive. “Not that you have to avoid vigorous workouts all together, but you should potentially reduce the number of sessions and intensity,” he says. For instance, swapping out your Barry’s Bootcamp classes with yoga or light walking, because these activities are generally much less likely to affect your chances of getting preggers, he says.

And if you’re a 22 year-old who’s not ready to get pregnant, says Dr. Reichman, you don’t need to worry about it at all. Just file this under “things to remember 10 years from now.” —Molly Gallagher