Moms who are running faster after having kids

“I regularly run at speeds I barely touched before children,” says 33-year-old Erin Lane, a Hyde Park mom to a five- and two-year-old, who is running this year’s Chicago Marathon. “Everything has increased—endurance, strength, lung capacity…appreciation for a quiet hour to run by myself, and confidence that I am a person who can do difficult things.”

Many active moms might be wondering what the heck is in the water at Lane’s house. (And can we have a sip of it?) After all, babies mean frequent sleep interruptions and getting comfortable in a new postpartum bod, toddlers demand constant chasing, and bigger kids require chauffeuring to a never-ending parade of piano lessons, play dates and sports practices. It translates to minimal time and even less energy to devote to running.

But Lane is not alone. At the elite level, it’s not uncommon for mothers who are also runners to bounce back into shape within months after giving birth. In April, elite long-distance runner Kara Goucher, then 32, took fifth place in the Boston Marathon, beating her personal record by a minute. She gave birth to her first child just seven months before toeing the line.

Research shows that there may be physiological benefits to having kids, from a tapering effect that allows chronic injuries to heal up during pregnancy to a surge in the hormone relaxin—which loosens pelvic and cervical joints for delivery, and hangs around the body after childbirth, possibly making a woman’s gait longer, smoother and more efficient. Also, pregnancy increases your blood volume, says Jim Pivarnik, Ph.D., a professor of kinesiology at Michigan State University who has studied pregnant athletes. As blood volume rises, so does red blood cell count, improving a woman’s efficiency at utilizing oxygen—which means running faster at the same effort.

The problem is that all of these effects are hard to measure. (Obviously, researchers aren’t thrilled with the idea of turning preggos into lab rats.) Pivarnik estimates that any residual blood-volume benefit has diminished by about eight weeks postpartum. And you’d be hard-pressed to find a woman—even at the elite level—who’d race that soon after having a child.

When it comes down to it, labor may make the most difference. Enduring hours of contractions and delivery—and sometimes C-section recovery to boot—may raise women’s pain threshold. Lincoln Square resident Jessi Merecki, a 38-year-old mom of two, says slashing 92 minutes off her pre-kiddos marathon best was due to “a combination of mental toughness from being a parent and physical toughness from childbirth.” She’s on to something, according to Pivarnik. “I would hypothesize that if being a mom is any help [to running], most of it would be mental,” he says. “Active moms may find that they’re more efficient and focused in training because they have so much more on their plates. It’s like that Yogi Berra saying, ‘90 percent of this is half mental.’ ”

Local moms—and other runners—pound the pavement in the Bank of America Chicago Marathon on October 9 at 7am. Check out our race coverage at timeoutchicago.com/marathon.