New mom Meghan Kita is committed to running. She once held the record for fastest marathon dressed as a fast food item, has logged about 32 kilometres a week for the last decade, and literally wrote a book loaded with running tips (How to Make Yourself Poop: And 999 Other Tips All Runners Should Know).

Still, she was surprised at how much breastfeeding threw off her game. “Breastfeeding made it impossible for me to run the way I used to,” she says. “I’d wake up way too full to run and didn’t have time to both pump and run before work,” she says. “My son was also eating frequently and irregularly, so finding a time to go out revolved around when he’d eat.” Add a lack of sleep and an overall decrease in mileage during pregnancy to the equation, and running became much harder, both physically and logistically.
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Of course, babies have a way of throwing off even the best laid plans, but there are extra things to consider when it comes to physically demanding hobbies like running. “People sometimes compare childbirth to running a marathon,” says Diane Spatz, Ph.D., professor of perinatal nursing at the University of Pennsylvania and manager of the lactation program at the Children’s Hospital of Philadelphia. “Both are physically (and mentally!) taxing and require proper recovery afterward.”

But assuming you have clearance from your doctor, you can absolutely run as a new mom, even while breastfeeding, as long as you’re prepared to make some changes to your schedule and goals.

“It’s important to start gradually and understand the changes that are going on in your body,” Spatz says. Keep reading to learn how these changes affect your running routine, including how to work around them wisely.

Pump Before You Run

Your breasts should be as empty as possible before you run, and to make that happen, Spatz suggests pumping a little longer than you think you need to. “All mothers have different patterns of milk ejection, so pump for two minutes after you see the last jetting of milk to be sure you didn’t miss any,” she says. Most women will have a few hours until they became uncomfortably full again.

Eat Enough

Lots of women say they feel ravenous when breastfeeding, so you might not exactly need a reminder to eat, but it’s worth saying anyway: It takes energy (read calories) to make milk. “If you were overweight or gained too much weight during pregnancy, you don’t need to up your caloric intake,” Spatz says. “But if you were at a healthy body weight before, then only gained the recommended weight during pregnancy, you should eat about 500 calories extra a day.” There’s no need to eat more beyond that unless you’re marathon training, but making sure you hit your overall caloric needs is crucial to keeping your energy up, Spatz says.

Also important: “Make sure you’re getting enough calcium (at least 1,000 mg a day), especially if you’re training at a high intensity,” Spatz says. Women can lose 3 to 5 percent of their bone mass while breastfeeding, according to the National Institutes of Health: “This bone loss may be caused by the growing baby’s increased need for calcium, which is drawn from the mother’s bones,” says the NIH. Low estrogen, which protects bones, may also play a role.

Buy a New Sports Bra

Most women go up a full cup size during pregnancy, then another cup size after delivery. So, yes, you’re going to need a new sports bra. Make sure to find one that’s supportive but not too restricting or tight (your nipples will thank you).

Stay Hydrated

“It takes fluid to make milk, so it’s important to stay hydrated,” Spatz says. The best way to tell: “Your urine should be pale and clear, not dark and concentrated.” That might mean taking water on the go with you.

Understand Your Hormones

Breastfeeding releases the feel-good hormone oxytocin, which encourages bonding and reduces stress, but it can also make you tired. Similarly, Spatz notes that cholecystokinin (CCK), another hormone released during lactation, makes you feel sleepy: “If you’re feeling super sleepy after pumping or breastfeeding, take a power nap and then head out for your run,” Spatz says.

Stash Milk at Home

Of course, your partner – or whoever is at home with the baby – will need bottles on-hand while you’re on your run. “The best way to store extra milk is to pump both breasts at the same time after a breastfeeding session, which is associated with improved breast emptying and higher milk supply,” Spatz says. “If the baby only eats from one breast, there will be a lot of milk in the breast the infant didn’t feed from.” And remember: “It’s supply and demand: If the baby doesn’t breastfeed from the breast – you’ll need to pump or your supply will go down.”

Go Easy on Yourself

Running is a big mood booster, which of course can come in handy as you face the challenges of new motherhood. But try not to let running become an extra source of stress. “I’m running a half marathon in a month, but training with a capital T isn’t super important to me right now,” Kita says. “I’m running enough to do it, but I’d rather be hanging out with my baby while he’s still a baby than striving for a PB.”

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