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10 Tips for Exercising and Breastfeeding

If you’ve been nervous about resuming exercise post-baby due to concerns about how it may impact your milk supply, you can relax. It is a myth that exercise decreases milk production. Studies have shown absolutely no difference in milk production or nutrient composition between those who exercise, and those who do not. Moreover, the American College of Obstetricians and Gynecologists (ACOG) states that “regular aerobic exercise in lactating mothers has been shown to improve maternal cardiovascular fitness without affecting milk production, composition, or infant growth.” That said, it’s a good idea to follow the 10 tips below to help both you and your little one have a better experience when nursing and working out.

  1. Feed your baby or pump prior to exercise to avoid exercise discomfort or engorged breasts.
  2. Wear a supportive, and well-fitted bra. Your breasts are larger and more sensitive, so proper support is imperative. Bras that compress are better than those that lift. However, it is also important to make sure the bra is not too small or too tight, as this can cause pain and impede milk production.  Try buying a bra from a store that will help fit you.
  3. Put on the bra just before exercising, and change it immediately afterward, to avoid discomfort or inhibition of milk production.
  4. Shower after exercising (if possible) or at least rinse your breasts before nursing, as your baby might reject the salty taste of sweat on your breasts.
  5. If you develop a plugged duct, cut back on exercise. A plugged duct typically comes on gradually and affects only one breast. You may notice a hard lump that feels tender, hot, swollen, or even a little red. In some cases, you may just feel tenderness without an obvious lump. It will typically feel more painful before a feeding, and less tender afterward. If you suspect you have a plugged duct, do NOT stop nursing, but cut back on exercise until it is resolved. Once the duct is cleared (typically rest, hydration, and proper nutrition can do the trick), resume exercise more slowly.
  6. STOP exercise if you develop mastitis. Unlike a plugged duct, mastitis is an actual infection where the inflammation is often accompanied by pain, heat, and redness, as well as fever, chills, and other flu-like symptoms.  A plugged duct can develop into mastitis if not treated promptly.  If you suspect you have mastitis, stop exercising and speak with your doctor immediately for proper treatment. Do not resume exercise until the infection has gone away.
  7. Stay hydrated. ACOG stresses the importance of adequate hydration prior to commencing physical activity. It’s also important to drink water during and after exercise. One helpful way to check if you are getting adequate hydration is to examine the color of your urine. It should be pale (straw-colored) to clear.  If your urine is darker or yellower, this is a sign of dehydration.
  8. Take a gradual approach to weight loss. It’s completely natural to want to begin working on post-baby weight loss. The old school of thought was that moms should not try to make dietary changes while breastfeeding. However, this is no longer the case, especially if you started your pregnancy at an overweight or obese weight status (2). That said, it is important to take a gradual and manageable approach to your weight loss efforts, as anything that puts too much stress on you could jeopardize your milk supply. Registered Dietitian and ProNatal Advisory Board Member Madison Milmeister recommends waiting at least 6 weeks to make big dietary shifts that promote weight loss. After that, ensure changes are gradual so that your body can adjust (physically and mentally). For example, begin by removing half of a regularly consumed snack (about 50-100 calories) for the first week or two. Then, once you can sustain this, gradually increase as the weeks go on.
  9. Take a gradual approach to resuming exercise. The same guidance above on nutrition applies to exercise. Any major jolt to your system could impact your milk supply, so resume exercise gradually. Begin perhaps with 2-3 days per week for 30-40 minutes each session (as you remove the calories mentioned above). Then, as your body adjusts, gradually increase exercise as the weeks go on.
  10. If your baby is rejecting your milk post-workout, wait 30 minutes.  In a small minority of women, very high-intensity anaerobic exercise may increase lactic acid levels in breastmilk enough to cause a sour taste and decrease infant suckling. If this happens, try pumping and discarding the breast milk for the immediate 30 minutes following exercise (this is the amount of time it takes for lactic acid to clear the breast). Or, consider simply waiting 30 minutes following exercise to nurse your baby.

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  1. American College of Obstetricians and Gynecologists, Committee Opinion #804. Physical Activity and Exercise During Pregnancy and the Postpartum Period.
  2. Lammi-Keefe, C. J., Couch, S. C., & Kirwan, J. P. (2018). Handbook of nutrition and pregnancy. Chapter 18. New York: Humana Press.