Exercise and Breastfeeding
By Mary Bibb, BA, IBCLC
Exercise is good for everyone, including breastfeeding mothers. Mothers who exercise have healthier hearts and tend to feel happier than those who don’t. Breastfeeding and exercise reduce stress and help to protect against depression. Mothers who exercise while dieting lose fat and not muscle. Exercise does not decrease milk supply. Babies whose mothers exercise gain as much weight as babies whose mothers who do not exercise.
Some mothers may have heard that exercise will make milk “sour.” Milk does not become unsafe in the breast, even if the mom gets hot or works hard. There is more lactic acid (a harmless substance that muscles make during exercise) in milk when mothers exercise strenuously. Exercising moderately does not increase lactic acid levels in milk. Very intense exercise does increase the amount of lactic acid in the milk, but this does not make the baby unwilling to breastfeed or take the milk from a bottle. Lactic acid disappears from milk quickly even after heavy exercise.
Exercise may be uncomfortable for some women if their breasts are full. Many women athletes find that exercise is more comfortable when they wear a supportive bra and feed the baby or pump beforehand.
Reviewed by Barbara Wilson-Clay, BSEd, IBCLC
Carey GB, Quinn TJ. Exercise and lactation: are they compatible? Can J Appl Physiol. 2001 Feb;26(1):55-75.
Carey GB, Quinn TJ, Goodwin SE. Breast milk composition after exercise of different intensities. J Hum Lact. 1997 Jun;13(2):115-20.
Dewey KG. Effects of maternal caloric restriction and exercise during lactation.
J Nutr. 1998 Feb;128(2 Suppl):386S-389S
Kendall-Tackett K, A new paradigm for depression in new mothers: the central role of inflammation and how breastfeeding and anti-inflammatory treatments protect maternal mental health. Int Breastfeed J 2007 Mar 30;2-6
McCrory MA, Nommsen-Rivers LA, Molé PA, Lönnerdal B, Dewey KG. Randomized trial of the short-term effects of dieting compared with dieting plus aerobic exercise on lactation performance. Am J Clin Nutr. 1999 May;69(5):959-67.
Sampselle CM, Seng J, Yeo S, Killion C, Oakley D. Physical activity and postpartum well-being. J Obstet Gynecol Neonatal Nurs. 1999 Jan;28(1):41-9.
Quinn TJ, Carey GB. Does exercise intensity or diet influence lactic acid accumulation in breast milk? Med Sci Sports Exerc. 1999 Jan;31(1):105-10.
Wright KS, Quinn TJ, Carey GB. Infant acceptance of breast milk after maternal exercise. Pediatrics. 2002 Apr;109(4):585-9.
Join the Medela family!
For exclusive offers, expert tips, and news directly from us first.