Breastfeeding and Exercise

Exercise and Breastfeeding
By Kelly Bonyata, IBCLC

Does exercise affect milk supply or nutrient content?
Does lactic acid increase in breastmilk after exercise?
Will baby refuse the breast after mom exercises?
Exercise guidelines for breastfeeding mothers
Additional information
Research
Does exercise affect milk supply or nutrient content?
No. Studies have shown no difference in the volume or composition of the milk or babies' weight gain. One study showed a slight increase in milk supply for the women who exercised regularly, but because of the small size of the study this increase may not be significant.



Does lactic acid increase in breastmilk after exercise?
Research has not shown a noticable increase in lactic acid buildup after moderate exercise (50% & 75% intensity). The lactic acid in breastmilk does increase somewhat if mom exercises to maximum (100%) intensity, also described as exhaustive exercise. This increase may be present up to 90 minutes post-exercise. There are no known harmful effects for the baby.



Will baby refuse the breast after mom exercises?
Most studies have found no difference in acceptance of the breast, even after maximum intensity exercise.

Although a highly publicized 1992 study indicated that baby might fuss or refuse expressed milk from a mom who had been exercising at 100% intensity, the results were questionable because the babies were fed the milk by dropper (unfamiliar to these babies), and the mothers reported that the babies had not had problems with nursing after exercise in the past. A more recent study showed no change in infants' acceptable of mom's milk an hour after exercise, even for the moms who exercised at maximum intensity (and thus did have a slight increase in lactic acid in their milk).

Dr. Ruth Lawrence, in her most recent volume (Breastfeeding, A Guide for the Medical Profession, 1999 edition) says that there is no reason to wait to nurse after exercising.



Exercise guidelines for breastfeeding mothers
For your own comfort, you may wish to nurse before exercising and wear a good, supportive bra (especially during strenuous exercises such as running, jumping, etc).
Some babies don't like nursing when mom has been sweating (due to the salt on mom's skin) so you may wish to rinse your breasts or take a shower before nursing.
If you regularly lift weights or do other exercises involving repetitive arm movement and you develop plugged ducts, cut back and start again more slowly.
Keep yourself hydrated.