Exercise and Breastfeeding: How Will it Affect My Milk?

Many moms have questions about exercise and breastfeeding. Some moms work really hard to build and maintain their milk supply, and they understandably don’t want to do anything that might compromise their baby’s food source! Fortunately, we have answers to your questions. The bottom line? Exercise and breastfeeding can absolutely go hand in hand.

Will my milk supply be affected if I exercise?

Research shows that breastfeeding mothers can exercise without risking a dip in supply. There appears to be no significant impact on the quantity (or quality) of breastmilk that is produced during or after exercise. 

Breastfeeding moms typically require more water than non-breastfeeding moms, and exercise can increase that need even more. You may find the need to prioritize water intake before and after exercise and throughout the day as you feel thirsty. Drinking to satisfy your thirst is usually sufficient for hydration and to support milk supply; more water will not necessarily help you produce more milk, so you don’t have to pack in a bunch of water if you’re not feeling thirsty.

Does working out affect the nutritional value of my milk?

There is some recent research showing that exercise can actually offer positive benefits to your baby for long-term health and weight management, similar to the benefits of exercise during pregnancy. This tells us it might be even more important to exercise while breastfeeding than we previously thought! 

According to some studies, there might be a very slight increase in lactic acid levels and changes in immune cell production for the first few minutes after exercising at 100% exertion, but all levels in the milk return to normal within an hour of completing exercises. If you’re not exercising to complete exhaustion but sticking around 60-80% intensity for a moderate exercise (which most of us do most of the time anyway), your milk will not be affected. Either way, you and your baby will still receive all the positive benefits of exercise over the long term. 

Will the taste of my milk change if I exercise?

No, it won’t! Any changes seen in breastmilk after exercise are short-term and relatively minor, and only occur with very high-intensity, strenuous exercise at near 100% capacity. For most postpartum women easing back into exercise up to 80% of maximal exertion, studies have shown no notable changes in breastmilk quality, quantity, or taste. 

If your baby is refusing your milk after a workout, try rinsing your breasts before you breastfeed to get the salty sweat off. They could also be distracted by activity at the gym or by the awkward pull of your restrictive sports bra, so it might help to take a moment to change clothes and move to someplace quiet and familiar for nursing. If you’re exercising at a very high intensity for more than 30 minutes, try waiting about an hour after exercise to allow any of the minor changes to return to normal.

I want to work out for weight loss. If I’m also restricting calories, will that impact my milk supply?

Restricting calories while breastfeeding is often discouraged by healthcare professionals, and for good reason. Breastfeeding requires up to 500 extra calories per day above your body’s baseline metabolic rate. No matter what your calorie intake, your body will still find a way to provide your baby with the nutrients they need through your milk. Restricting calorie intake could create a nutritional deficit, which would cause breastmilk nutrients to come directly from your body. This could put you at risk for bone health issues, cardiovascular damage, and hormone imbalance. Eating enough while you’re breastfeeding is important for your well-being! Consider focusing on a healthy diet – eating only whole foods, lots of vegetables and protein, and cutting down on unnecessary sugar if your goal is to lose weight or body fat, rather than restricting calories altogether.

That said, losing pregnancy-related weight postpartum is an important goal for many new moms. Some women find it easy to lose weight while breastfeeding because of the increased calorie burn, and other women find that hormones make it much more difficult to drop weight while still breastfeeding. Fortunately, exercise routines plus healthy eating is an excellent way to increase your muscle mass and reduce body fat without risking your milk supply or your own body’s health.

Will exercising contribute to plugged ducts or mastitis?

Exercise alone should not contribute to plugged ducts or mastitis, but there are numerous factors that could contribute to an issue. If you’ve just started exercising and you’re noticing more plugged ducts, check that your sports bra is well fitted and not pinching over breast tissue or under your arms, and limit the time you’re wearing a compressive sports bra before and after your workout. Try to remove milk from your breasts before exercising by nursing or pumping, and again soon after you’re done. If those strategies don’t help, you may need to back off the intensity or duration of your exercise and slowly ramp back up once the plugged ducts are resolved. 

Stretching your chest muscles and gentle massage to the breast tissue can also be helpful for plugged ducts, as it promotes circulation and mobility in the whole chest region. Other strategies for plugged ducts can include moist heat, vibration, positioning strategies, and therapeutic ultrasound. If you’re experiencing plugged ducts on a regular basis, consult with your healthcare provider or a lactation consultant to troubleshoot and figure out the best plan for you. 

I find working out to be really uncomfortable because my breasts feel tender. What can I do to make it easier?

If you’re diligently emptying your breasts before a workout and wearing a well-fitting sports bra but you’re still feeling tender, you may want to consider a few other things.

  • There are sports bras available that are adjustable with velcro straps, both specifically made for nursing moms as well as for the general population. This can be a good option if you’re not able to remove milk for an extended period and need different levels of support as the hours pass. It can also make it easier to breastfeed your baby immediately after a workout without having to change clothes. 
  • The pectoralis muscles sit directly beneath the breast tissue, so if you’re working them hard they can become sore and make the whole area feel tender. Exercises that use the pectoralis muscles include push-ups, planks, and chest presses, among others. You can certainly include these exercises in your workout routines, but be sure to gradually build intensity and stretch them out in the hours and days afterward to help manage any post-workout soreness.
  • Sometimes it takes a few months for your milk supply to regulate, and engorged breasts can be uncomfortable regardless of your exercise status. You may need to slow your pace just a little to keep you comfortable and give your body time to adjust to your baby’s needs. 

In summary, exercise of all kinds is good for nursing mothers AND their babies. If you’re noticing changes in your milk production or baby’s behaviors when you start exercising, try some of the ideas suggested above and reach out to a certified lactation consultant to discuss what other factors might be contributing.

About the Author

Dr. Samantha Spencer, PT, DPT, is a Medical Advisor with Aeroflow Breastpumps. Dr. Spencer is a physical therapist who specializes in pelvic and perinatal care in the Asheville, NC, area where she offers in-home physical therapy to prenatal & postpartum individuals. She also developed the Strong Beyond Birth 28-Day Course to guide and support moms as they return to exercise, and offers virtual consultations to women everywhere.

Information provided in blogs should not be used as a substitute for medical care or consultation.