We know that exercising in pregnancy has so many benefits for mom and for baby, and they don’t stop once you deliver, either. But for moms who are breastfeeding, many wonder if exercising can cause problems with nursing because of things they’ve been told or have read.

After you’ve given birth, your doctor or midwife will give you the green light to resume your normal pre-pregnancy activities around 4-6 weeks postpartum (as long as you’ve had no complications). These include things like having sex, taking baths, and exercising. Common sense prevails when it comes to returning to exercise, with most medical providers recommending a gradual return to activity. This is so you don’t overdo it and you go easy on your newly postpartum body (that is likely very fatigued from sleep deprivation!).

Breastfeeding moms may worry that exercising might be problematic. Some have been told that exercise is too uncomfortable and will cause too much breast pain, while others have heard that it will make their milk taste sour to their baby or will even decrease their milk supply. Luckily, these fears are mostly unfounded!

It can be true that vigorous exercise like running can be uncomfortable if a woman hasn’t nursed in four hours and her breasts are very full. To deal with this, try feeding or pumping right before you work out. A supportive, well-fitting bra is an absolute must, and sometimes finding the right one is trial and error. With these conditions met, most women find they are perfectly comfortable exercising.

As for milk tasting sour after a woman exercises, this tends to be based on the fact that exercise increases the levels of lactic acid in our bloodstream. It is true that lactic levels do rise in breast milk as well, but this is only with very intense exercise. Even so, many babies nurse happily and notice no change in taste (and the lactic acid disappears quite quickly). Therefore, a woman should not be afraid to exercise based on this fact alone.

Luckily, many women see no change in their milk supply with exercise. If this concerns you, wait to exercise until nursing is well established (which is usually around six weeks postpartum). Stay hydrated during your workouts and make sure you are eating enough calories, and more likely than not, you will have no issues with milk supply related to your exercise habits. In addition, avoid exercising extremes, and you should be just fine.

Keep in mind that women who exercise are healthier, and this applies to breastfeeding moms, too! Breastfeeding naturally decreases a woman’s calcium stores in her bones, and studies have actually shown that exercising during breastfeeding keeps more of that calcium in her bones. Therefore, from the benefits to your heart, your waistline, your bones, and even your mood – exercise and breastfeeding can certainly exist together safely.


  • Many breastfeeding moms worry that exercising can cause issues with nursing.
  • To be more comfortable while working out, feed or pump just beforehand and wear a supportive bra.
  • Many babies nurse happily and notice no change in the taste of milk if their mom exercised.
  • Exercising during breastfeeding can help increase a woman’s calcium levels in her bones.

Last reviewed by Sara Connolly, MD. Review Date: March 2020


  1. American College of Sports Medicine. Exercise during lactation.
  2. Medela. Exercise and breastfeeding.
  3. American College of Obstetricians and Gynecologists. Physical Activity and Exercise During Pregnancy and the Postpartum Period.


  1. After my first baby, I started a very intense workout regimen. However, my personal trainer was very careful to advise me on caloric intake, even providing a specific required daily number of calories to make sure my milk production wasn’t affected. I never had a problem with breastfeeding at all, and hope the same will be true with my next baby! I will say that in addition to making me feel better about my body, working out did wonders for my mental health. It was the only time in those early months postpartum when I got a moment alone.


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