Postpartum Exercise and Its Affect on Breastmilk & the Newborn

Exercise isn’t for everyone, but it’s not said enough how much it can help a new mothers life, both physically and mentally. And no, this is not a man just ‘mansplaining’ because he likes the sound of the ‘clicks’ and ‘clacks’ of the keys on his keyboard as he types. This man actually found the research that states why exercise is recommended for several reasons, one of them being the future health of your little newborn beauty.

To begin, the process of lactation and breastfeeding within a new mother’s body is going to begin whether or not that mother has plans to breastfeed- that’s just how mother nature made these lifegivers (1,2). However, what most women don’t know is that during this process of making colostrum (beginner breastmilk), and then full on breastmilk, a mother’s body is drawing on all bone stores to help with the calcium uptake in this newly made milk (2) which leads to decreased bone mineral density. 

Density?! Yes, bone density. Put plainly, your bones are made up of calcium, fat and all other things, but it's the calcium that makes them strong (those “drink your milk kids” commercials were correct in a way), and when your bones are lacking in calcium it makes them weaker and more prone to breaking. In recent studies it was shown that breastfeeding mothers lost 3-9% of their bone mineral density in just 2-6 months (2). So then what is the answer to help reverse this phenomenon? Exercise! A study by Sowers et al. (1993) found that there were less bone density losses in postpartum mothers who exercised compared to those who didn’t. But does all this exercise to save one’s bones affect breast milk? After all, you are possibly inviting exercise related metabolites (results of your metabolism revving up while exercising) into your breastmilk. Let’s see….

Breastmilk’s composition, along with calcium, is made up of phosphorus, magnesium, sodium, potassium- all vital nutrients for a growing newborn to have (3). But exercise causes an increase in things like lactic acid and lactate, and so the thought has been, “my breast milk will replace those vital nutrients with lactic acid.” Science says, no! When postpartum women exercise they have the same concentration of those nutrients, and there have been no decreases in volume of milk with exercise alone, or with caloric restriction (aka aiming to lose weight) (4-9). 

But now what about the newborn and exercise’s effect on them? How the hell is mom doing hip bridges and planks going to help a barely awake newborn? Well, the answer is quite simple- by watching mom do exercise those children are more likely to grow up to be healthier individuals. Researchers have found that parental exercise was the single biggest thing to influence a child’s level and frequency of physical activity and their fitness level (10-14) and by showing your children healthy habits you could reduce a child’s long-term risk for chronic diseases such as coronary artery disease, hypertension, type 2 diabetes, and osteoporosis (1). 

With all that being said, what’s stopping you from setting yourself and your children up for physical success?

-Coach Khalil Harrison

References

1. Larson-Meyer D. E. (2002). Effect of postpartum exercise on mothers and their offspring: a review of the literature. Obesity research, 10(8), 841–853. 

2. Cross, N. A., Hillman, L. S., Allen, S. H., Krause, G. F. (1995) Changes in bone mineral density and markers of bone remodeling during lactation and postweaning in women consuming high amounts of calcium. J Bone Miner Res 10: 1312–1320

3. Sowers, M., Corton, G., Shapiro, B., et al. (1993) Changes in bone density with lactation. JAMA 269: 3130–3135.

4. Ritchie, L. D., Fung, E. B., Halloran, B. P., et al. (1998) A longitudinal study of calcium homeostasis during human pregnancy and lactation and after resumption of menses. Am J Clin Nutr 67: 693–701.

5. Hopkinson, J. M., Butte, N. F., Ellis, K., Smith, E. O. (2000) Lactation delays postpartum bone mineral accretion and temporarily alters its regional distribution in women. J Nutr 130: 777–783.

6. Little, K. D., Clapp, J. F. (1998) Self-selected recreational exercise has no impact on early postpartum lactation-induced bone loss. Med Sci Sports Exerc 30: 831–836.

7. Lovelady, C., Lonnerdal, B., Dewey, K. (1990) Lactation performance of exercising women. Am J Clin Nutr 52: 103–109.

8. Dewey, K. G., Lovelady, C. A., Nommsen-Rivers, L. A., McCrory, M. A., Lonnerdal, B. (1994) A randomized study of the effects of aerobic exercise by lactating women on breast-milk volume and composition. N Engl J Med 330: 449–453.

9. McCrory, M. A., Nommsen-Rivers, L. A., Mole, P. A., Lonnerdal, B., Dewey, K. G. (1999) Randomized trial of the short-term effects of dieting compared with dieting plus aerobic exercise on lactation performance. Am J Clin Nutr 69: 959–967.

10. Lovelady, C. A., Garner, K. E., Moreno, K. L., Williams, J. P. (2000) The effect of weight loss in overweight, lactating women on the growth of their infants. N Engl J Med 342: 449–453.

11. Carey, G. B., Quinn, T. J., Goodwin, S. E. (1997) Breast milk composition after exercise of different intensities. J Hum Lact 13: 115–120.

12. Quinn, T. J., Carey, G. B. (1999) Does exercise intensity or diet influence lactic acid accumulation in breast milk? Med Sci Sports Exerc 31: 105–110.

13. Gottlieb, N. H., Chen, M. S. (1985) Sociocultural correlates of childhood sporting activities: their implications for heart health. Soc Sci Med 21: 533–539.

14. McMurray, R. G., Bradley, C. B., Harrell, J. S., Bernthal, P. R., Frauman, A. C., Bangdiwala, S. I. (1993) Parental influences on childhood fitness and activity patterns. Res Q Exerc Sport 64: 249–255.