Breastfeeding - Is it Safe to Exercise?

So ... you've decided to breastfeed.  You also want to get back in shape following your baby.  While breastfeeding is a huge topic of conversation, there's not as much talk about breastfeeding and exercise.   Here's a few questions you may be asking ...

Will baby refuse the breast after exercise?  You may have heard that babies don't accept breast milk as readily after mom has exercised because of a buildup of lactic acid.  However, most studies have found no difference in acceptance of the breast, even after maximum intensity exercise.  Research has also not shown a noticeable increase in lactic acid buildup after moderate exercise.  Even with maximum intensity exercise where there is a minimal increase in lactic acid in breast milk, there are no harmful effects for the baby.  While there may be a change in taste of breast milk from lactic acid, babies will not subsequently refuse to breastfeed because of it.  More plausible reasons for why your baby may refuse to breastfeed after you exercise are issues such as the salty taste of sweat on your breast post-workout.


Is the composition of antibodies of breast milk affected by exercise?  Exhaustive exercise does cause IgA levels (a type of antibody) to decrease for a short amount of time.  However, these levels return to normal within an hour - a decrease in IgA levels in one feeding per day is not likely to be significant.  Moreover, moderate exercise does not affect antibody levels.


Is your milk supply affected?  In short, no.  In fact, some studies have shown that women who exercise regularly had a slight increase in milk supply.  However, if you exercise to the point of exhaustion, or train for an event such as an Ironman, your body may be depleted to the point where producing milk is its last priority.  Bottom line - moderate, regular exercise should not affect your milk supply.


What types of exercise are best?  There really is no "best" type of exercise for breastfeeding moms.  It's really more about what you enjoy and what makes you feel good.  Because breastfeeding moms are a bit more top heavy, things like running may be more uncomfortable, but it can still be done with the right type of support/attire.

What attire provides the most support for breastfeeding moms?  The key to being comfortable while exercising is finding a good supportive bra that fits you.  I would suggest getting measured at a sports specialty store for women (e.g. Athleta, Title Nine, etc) so that you know exactly what you need.  It really does make a huge difference.  You can avoid the two sports bra routine if you find the right bra that fits you :)


Other tips ...  Definitely try to breastfeed right before a session of exercise.  Clearly, this is more comfortable, especially for weight bearing activity like running.  You may develop plugged ducts if you  lift weights involving repetitive upper arm strengthening (if that happens, start with lower weight/reps).  And make sure you drink and stay well hydrated!!

Rachel Brewer, MD