Mom UP

Exercise And Lactation

7 minutes

Christy here to talk about exercise and lactation. Most mamas are eager to get back into a regular workout routine postpartum and I was totally in that same boat, but the other question that comes up is whether exercise impacts breastfeeding and milk supply/quality. I personally did a little research when I started working out more vigorously postpartum, but I wanted to dive a little deeper to ensure I was sharing the best knowledge. Ives was kind enough to pass on some scholarly literature she has access to, to aid in my research.

Hiking in Kauai, clearly breastfeeding while staying active isn't perfect.

I also know that this is a sensitive subject and I by no means am an expert in this area, so please consult your doctor for medical advice before beginning exercise postpartum. I’m simply a new mama sharing my journey and research along the way in hopes of helping others in the same boat. As a reminder, it is typically recommended to wait 6-8 weeks before beginning regular exercise. This will look different for everyone based on their individual recovery.  

When I first began researching exercise and lactation, I was happy to learn from various sources and studies that participating in regular, moderate to intense exercise postpartum does not impact milk supply, quality, or a baby’s growth once a woman’s milk supply is established (through supply and demand) and in fact has so many benefits! The caveat being that every woman is different and in scenarios of extreme diet restrictions and/or high levels of exercise intensity that vary drastically from what the woman was doing prior or during pregnancy, it is possible to experience milk drop off.

In general, breastfeeding typically shouldn't be a time to cut back on calories and personally, I'm not focusing on any specific goals besides feeling as good as I possibly can with all of the changes and challenges a new mom is up against. The postpartum phase is such an important time to nourish your body and ensure you are not only adequately fueling yourself but also finding the time to move or more importantly, find time for yourself.

According to, a website developed to provide evidence-based information on breastfeeding and parenting, “Moderate exercise improves a mother’s health and has a positive effect on her emotional well-being”. So mamas, I'm a huge advocate of letting go of the mom guilt in order to spend some time giving back to yourself!

Photograph: Alexis Berg/AFP/Getty

As ultra runner Sophie Power put it, when a picture was snapped of her as she breastfed her son Cormac during the 105-mile Ultra-Trail du Mont Blanc race, “It has highlighted something that women feel really unable to talk about. There is this huge mother’s guilt that all the time you need to be 100% focused on your baby, and I’m saying that by not focusing on your own physical and mental health you can’t be the best mother. For me, personally, I need to be physically fit and have those mental breaks. Women really struggle to be open about saying that.”

I couldn't agree more and is yet another reason I wanted to research and shed light on exercising while nursing. Let's dive into some of my key findings which include milk composition changes, lactic acid in milk, and calories/nutrition needed during exercise while nursing.  

Milk Composition Changes:
​Although research has shown that exercise does not impact lactation as noted above, I want to give you all sides of the story.

According to (also noted above), “Exercising to exhaustion may have a short-term effect on  IgA content of a mother’s milk”. This is based off a few small studies. If you don’t know what IgA is, like yours truly… after Googling it, I learned that it is one of the most common antibodies in the body. We need IgA to fight bacteria, viruses, and toxins. The decrease in IgA after intense exercise is however very short lived, 10-30 minutes and levels return to normal within the hour. Also, a decrease in IgA in one feeding per day is very unlikely to make a difference on your infant’s health.

Lactic Acid and Milk Taste:
The other worry some mamas have is lactic acid in breast milk. Lactic acid does not harm your babe, but can change the taste of your milk. Apparently there was a highly publicized study in 1992 indicating that a baby may refuse expressed milk from a mom that has been exercising at 100% intensity. Please note that the babies in this study were fed milk by a dropper and not from the natural source, the nipple.

I personally have had no issues with this and there are times where I do workout at a high intensity, but it’s still something to consider as you begin to increase your workout intensity.

​If you notice an issue, the advice is to wait an hour after intense exercise before feeding/pumping. Simply pay attention to whether your baby consistently rejects your milk after exercise, talk to your doctor, and make adjustments as needed.

Okay, so now that we can assume it’s okay to exercise and breastfeed, let’s talk hydration. Hydration is key for keeping up your milk supply, even if you aren't exercising. Exercise causes you to sweat (we love this), and lose water that then needs to be replenished following exercise. Everyone is going to be slightly different with the amount of water they will need to drink, but a good rule of thumb is to ensure your urine is clear.

If you are a numbers person, The Institute of Medicine says that on average a breastfeeding mother should consume 3.1 liters which equates to 13 cups, compared to 2.2 liters or 9 cups for non-pregnant/lactating women. These are just guidelines and remember, you know your body best.

A personal tip is purchasing  a hyrdoflask tumbler with a lid and straw! Having cold water nearby that was easy to sip from a straw (and didn't spill, because it was knocked over often) seriously made a world of difference. My Hyrdoflask tumbler was 22 ounces, so my goal was to fill it up 4-5 times a day!

Calories in Vs. Calories out:
I don’t count calories or weigh myself, but it's important to touch on and based on my research your caloric intake should not fall well below the amount of calories you are burning in a day (less than 20-25%). Keep in mind, on average, you are burning 300-500 extra calories per day when breastfeeding/pumping.

My personal advice and what has worked for me is to eat when you are hungry and to eat nutritionally dense foods. I breastfeed approximately 3X a day and pump 2-3X during the work week. I typically eat 3 meals a day and 3-4 small snacks. This includes fresh fruits, vegetables, healthy fats, whole grains and legumes, and lean proteins. Having easy, healthy snacks easily accessible is key!  Chopping up veggies to eat with hummus, making my lactation energy balls, or having nutritionally dense bars stashed away, such as RX, Lara, or PerfectBars are great options.

Want to lose weight post pregnancy?:
Based on my research, if you are trying to lose weight the key is to not drop more than 3/4 a pound to a pound per week. Drastic weight loss could impact milk production. Just like exercise during pregnancy, however you were eating prior or during pregnancy will not have a major impact on your milk supply. So what this means is that with any calorie deficit changes, the key is to start slowly. It took almost a year for your baby to grow inside of your changing body, so keep that in mind and be kind to yourself as you try to meet your goals.

Nutrition Takeaways:
When it comes to nutrition both postpartum and to help with lactation, there is a lot of information out there, but some key takeaways I learned specific to exercise and lactation were around protein and calcium intake.

In regards to protein, it's recommended to keep your intake up to prevent loss of muscle mass (Recommended Intake of protein for nursing mothers is 65 grams/day for the first 6 months and 62 grams/day between 6 and 12 months). Below are some practical foods guidelines.

  • 1 egg = 7 g protein
  • ¼ cup black beans = 4 g protein
  • 16 ounce serving greek yogurt= 12-17 g protein
  • 2 Tbsp peanut butter = 7 g protein
  • 1 oz. meat = 7 g protein

For calcium, it is recommended to get at least 1,000 mg a day, "especially if you’re training at a high intensity,” recommends Diane Spatz, P.D., professor of perinatal nursing at the University of Pennsylvania and manager of the lactation program at the Children's Hospital of Philadelphia. From an article pulled from, "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.

Don't think you have to go chugging milk... dairy products are obviously rich in calcium, but here are a few other sources outside of the dairy family, rich in calcium:

  • seafood (canned salmon and sardines)
  • leafy greens (collard greens, spinach, and kale)
  • ​According to, 1 cup of cooked collard greens packs 25% of your daily calcium needs
  • seeds (chia, poppy, and sesame)
  • beans and lentils
  • Almonds

There is no such thing as a perfect diet and sometimes it's just ensuring you are eating enough, never deprive yourself. Your body is working hard to produce milk and it's okay to treat yourself even if it doesn't fall into these guidelines. As they are just that, guidelines that I found interesting and helpful as I continue to stay active and especially as I plan to pick up my exercise intensity now that I feel my body has healed from birth.

Whether it's adding more protein or calcium into your diet or maybe just letting go of the mom guilt you may be feeling when you leave the house to get a work out in, I hope you found this information helpful! Whether you are a breastfeeding mama or planning to breastfeed one day while staying active, let me know your thoughts and/or experiences below!