Is Breastfeeding affected by Running?

Many mamas choose to breastfeed, and many choose to do so beyond the first year. There are a lot of moms who report difficulty with breastfeeding once they return to regular or more intense exercise. Some of these things include struggling with joint pain, milk supply, bra fit, and clogged ducts or mastitis. Here are a few things to keep in mind when gradually returning to your regular exercise or run routine.

Black and white image of mother holding baby breastfeeding.

The Role of Relaxin when Breastfeeding

Newer guidelines are suggesting that relaxin stays in the body up to 3 months AFTER you FULLY wean from breastfeeding.

This means that you have increased ligamentous laxity throughout the body. This can put you at increased chance of injury. It’s not uncommon for new moms to report hip or knee joint pain following delivery and even more so when they return to running.

It’s really important to make sure you’re incorporating strengthening into your regular exercise program. It’s not enough to just run.

Let’s Talk Sports Bras and Breastfeeding

All sports bras are not created equal. Additionally, I’ve read (somewhere) that your sports bra shouldn’t see a first birthday. They lose their support and elasticity after a year of wash and wear.

For most women, your size will increase during pregnancy and then again after Baby arrives.

The message here is: Take your measurements and get refitted after you have Baby and then again once your supply settles or evens out.

Boob or Bust is a great FB group with a measuring guide and takes into consideration whether you’re breastfeeding.

To avoid dealing with clogged milk ducts that can turn into mastitis, make sure to choose more encapsulated cups over compression style bras.

My favorite Pregnancy and Postpartum Sports Bras

Brooks Juno and Fiona

These are great because they have adjustable straps from the FRONT and a hook and eye clasp in the back. These bras are great for adjusting based on fluctuating fullness.

The shoulder straps also are completely removable from the front, so you can drop one side for breastfeeding a hungry baby right after your run.

Brooks Spring Dare

This one is my new favorite. It has a zippered front. This makes it a great exercise bra because it’s easy on and easy off. In the postpartum period, you can unzip to nurse Baby.


This company makes amazingly supportive bras in an array of many sizes. Again, a hook and eye closure helps to adjust based on your size at any given time.

Another reason I recommend all these bras because they all go by band and cup size, not just S/M/L, which provides for a much better fit. A better fit means increased comfort, less chance for chafing and less chance for clogged ducts.

Breastfeeding Before/After Exercise

Head out for your run or workout with “empty” breasts.  Make sure you’re breastfeeding or pumping just prior to exercising. This will make you a lot more comfortable while running or performing higher impact activities.

Nurse again when you get back in or finish your workout. It might not have to be right away, pending the time elapsed since you last nursed and Baby’s age. But I would say this is definitely true in the earlier months. If Baby is ravenous, don’t be afraid to nurse even before showering! Most little ones don’t care if you have a sweaty boob!

Wear Your Bra for Exercise Only

Put your bra on right before you head to the gym, or get on the road/treadmill, and then take it off as soon as possible afterwards.

This will minimize how long you’re in a compressive or restrictive garment and thus decrease your risk for clogged ducts.

Maintaining Breastfeeding Supply

Did you know? Calorie demands while breastfeeding are higher than those while pregnant.

When you’re pregnant, from the 2nd trimester on, you need about 200-300 more calories a day. However, when you’re nursing, you need about 500 more calories a day.

You’ll also need to account for your energy expenditure from your exercise! Make sure you are eating enough good, healthy food to make up your caloric deficit!

Lactation Product Myth

Most “lactation” products, like teas, cookies and the like, don’t really help, to be honest.

Supposed milk boosting ingredients are known as galactagogues. Some, like fenugreek, can actually harm supply rather than help it.

Focus on good, healthy whole foods instead of products that tout increasing supply.

Eat Carbohydrates!

Make sure you’re eating enough carbs (I know, I know), but carbs contribute to good supply. Many moms make the mistake of trying to cut calories or even cut carbs or food groups in efforts to lose pregnancy weight. Some can do it successfully, but I’d say for the most part, you really need to keep eating “good” carbs to maintain your supply.

If you’re within the first year postpartum, you really shouldn’t worry too much about your weight or weight loss. I know this is easier said than done. However, it took you 9 months to gain the weight and now as a breastfeeding mama, you’re still supporting you plus one.

Your body knows exactly what it’s doing to maintain your and your baby’s health. Trust that.

Drink Lots of Water

Make sure you’re drinking enough water! If your supply seems like it’s dipping, up your intake. There are lots of different guidelines out there as to how much you should drink. Some say a gallon a day. Some say half your body weight in ounces. Others say 2L/day.

I’d say, drink enough so that you don’t feel thirsty. If you’re thirsty, then that’s a sign that you’re dipping into dehydration phase.

And if you feel like your milk output isn’t as great as you want it to be, add in an extra glass or two of water daily.

Nurse, and Then Nurse Some More

Make sure you’re nursing on demand and that you’re nursing enough around the clock. And I don’t mean just before or after exercise.

I mean in general.

For the first 12 months, in order to maintain adequate supply, lactation specialists recommend nursing every 2-3 hours (or more, if Baby wants) with one five hour stretch overnight.

Additionally, make sure that whenever you’re with Baby, you’re nursing instead of pumping (this obviously doesn’t apply if you’re exclusively pumping). Nursing will stimulate supply better than a pump can. And it’s all about demand = supply.

Try Not to Stress about Breastfeeding

Thinking about your supply and stressing whether it’s enough can actually cause your supply to dip!!

Stress is an inhibitor to milk production. I know it’s hard not to stress about it, however, if Baby is growing adequately and having enough wet and poopy diapers, then he/she is getting plenty!!

Breastfeeding and Periods

So, depending on when your period returns postpartum, you may notice a temporary dip in your supply. This can happen at the time of ovulation and/or the time of your actual menstruation.

Again, don’t stress. Just continue to nurse on demand (Baby may want to nurse more during these times), increase your water intake, etc. It will bounce back in a few days. This is normal!


Some mamas are the exception to the rule and no matter whether they follow all of the above, they find that they still can’t maintain adequate supply with exercising intensely.

However, know that these mamas are the exception and not the norm.

Most women can and do maintain a healthy breastfeeding supply while picking up the duration and intensity of their running and/or workouts.

Prepare to Return to Run Postpartum

Before you actually start running again after your have your baby, make sure that your core and pelvic floor are ready for it. To get started, get your comprehensive PDF guide of Postpartum Pelvic Floor Exercises. You can start doing these exercises the day you give birth, weeks, months or years after so you can start the recovery process and prepare for returning to run. These exercises will help improve your posture, realign your spine and help with your pelvic floor health. Click HERE for your Guide.

Rachel holding her kids in front of her house

Get back to normal. Get back to running.

I help Moms at all stages of postpartum get back into running successfully to relieve pain, remove discomfort and enrich lives.

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