Postpartum fitness | Breastfeeding and exercise

Snatching postpartum
Andrea Signor snatching with the Buband, a much appreciated extra support band for the girls.

A big concern for women hoping to return to the gym is how her workouts may impact breastfeeding. The old school way of thinking was that if a woman exercised, the lactic acid that built up would result in a sour tasting milk.

In his chapter on breastfeeding and exercising in “Exercising Through Your Pregnancy,” Dr. James F. Clapp writes, “The concern that regular exercise during lactation alters the quality and quantity of the breast milk had its origins in the dairy science literature, which indicated that even modest increases in physical activity decreased milk production in cows.”

Because breastfeeding moms are equivalent to cows.

Other medical studies from the early 1990s reinforced this theory, however, Clapp writes, the findings were misconstrued and spin-off studies conducted by nutritionists found that “frequent, sustained, moderate- to high-intensity running during lactation did not impair the quantity or quality of human breast milk.”

Breastfeeding USA writers Jennifer Palmer and Sharon Knorr second these findings.

“A couple of small studiesĀ found no difference in immunologic factors after moderate exercise, but they showed a decrease in immune boosting proteins after exhaustive exercise,” they write. “Levels return to normal within an hour, and the impact on baby is unlikely to be significant.”

Losing weight while breastfeeding

Another concern for breastfeeding women anxious to return to the gym is whether losing weight will affect her supply.

Clapp, again, comes to the rescue. In his research, he found that women who continued to consume 1,500 calories or more per day were able to lose weight and continue meeting their infant’s milk needs.

Of course, every woman’s caloric needs are different and 1,500 calories is just an approximation. But Clapp’s research found that women who consumed fewer than 1,500 calories experienced a decrease in production and infant weight gain decreased as well.

“The threshold for this effect is when calories in are about 20 to 25 percent below calories out,” Clapp writes, adding that frequency and duration of feedings may also impact supply.

Postpartum nutrition

Assuming a breastfeeding woman consumes the minimum number of calories to keep up her supply, she may be curious as to which foods are the best to assure she and her baby are getting the appropriate nutrients.

In a BirthFit blog post, coaches encourage a postpartum woman to eat protein before working out and consume a carbohydrate, such as sweet potatoes, within 30-90 minutes after completing a workout.

It’s also important for a breastfeeding woman to continue taking prenatal supplements as well as iron, calcium, and a quality fish oil.

Disclaimer: Andrea Signor is a writer. She does not have any medical background or fitness certifications. She is a former journalist with an interest in weightlifting. Any woman interested in exercising and lifting in her pregnancy should consult with her medical team and fitness coaches.

Want more? Read part three of our series: Do’s and Dont’s for postpartum fitness

Missed Part One? Check out our tips for postpartum weightlifting here.

15 Replies to “Postpartum fitness | Breastfeeding and exercise”

  1. I’m not a mom, but I have many friends that are breastfeeding moms that have worried about how their workouts will affect their breastfeeding. I’ll definitely share this blog post with all of them!

    1. Thank you, Susie, for reading. I hope folks find it helpful and useful. I’ll continue to add to it in the months to come.

  2. Even though my kids are in their 20s, I am loving these posts! I never heard of the ‘sour milk’ with exercise. I worked out with all of my kids starting at 2 weeks post-partum (even after my c-section) and none of them seemed to complain!

  3. I never heard about the sour milk concern before, though I do know some women who struggled to keep their milk supply up while also exercising. Thankfully, I had more than enough milk for my little man, even with returning to exercise only a couple of weeks after delivery. I was eating like a cow though, yet somehow managed to be the smallest I have ever been while I was breastfeeding. Nonetheless, I had more than enough milk for my baby.

  4. I was fearful of keeping my milk supply up when I returned to exercise only a couple of weeks after delivery. Thankfully, I didn’t struggle to do so. Even though I felt like I ate like a cow, I was the smallest I have ever been while I breastfed. I’m so thankful that my exercise didn’t affect my milk supply because exercising helped me to feel like “me” again.

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