Should breastfeeding mothers with normal Body Mass Index (BMI) avoid strenuous exercise?

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Last updated: March 11, 2025View editorial policy

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From the Guidelines

Breastfeeding mothers with normal BMI do not need to avoid strenuous exercise, as moderate to vigorous physical activity is safe and beneficial for most lactating women, provided they stay well-hydrated, consume adequate calories to support milk production, and feel comfortable during exercise. According to the most recent and highest quality study, 1, country-specific postpartum guidelines for physical activity and sedentary behavior can help promote healthy behaviors using a culturally appropriate context while providing specific guidance to public health practitioners. The benefits of exercise for breastfeeding mothers include:

  • Improved cardiovascular fitness
  • Better mood
  • Reduced stress
  • Assistance with gradual return to pre-pregnancy weight
  • No significant impact on breast milk quantity, quality, or infant growth, as stated in several guidelines 1. Some key considerations for breastfeeding mothers who exercise include:
  • Staying hydrated to support milk production
  • Consuming adequate calories to support milk production
  • Wearing a supportive sports bra
  • Feeding or pumping before exercise
  • Watching for signs that exercise is negatively affecting milk supply, such as decreased output or baby's dissatisfaction after feeding, and adjusting intensity accordingly. It is essential to note that very intense exercise might temporarily increase lactic acid in breast milk, causing a slight taste change, but this does not harm the baby and usually resolves within 90 minutes post-exercise. Overall, the benefits of exercise for breastfeeding mothers with normal BMI outweigh the potential risks, and they can safely engage in moderate to vigorous physical activity, as supported by the latest evidence 1.

From the Research

Breastfeeding and Exercise

  • The provided studies do not directly address whether breastfeeding mothers with normal Body Mass Index (BMI) should avoid strenuous exercise 2, 3, 4, 5, 6.
  • However, the studies suggest that moderate exercise can be beneficial for breastfeeding women, particularly those who are overweight or obese, as it can help with weight loss and improve overall health 2, 3, 4.
  • One study found that aerobic exercise of 45 min/d, 5 d/week improved cardiovascular fitness, plasma lipids, and insulin response in breastfeeding women, but did not promote post-partum weight loss 3.
  • Another study found that gradual weight loss (< or = 2 kg/mo) seems to have no adverse effect on milk volume or composition, provided that the mother is not undernourished and is breast-feeding her infant on demand 4.

Maternal Body Mass Index and Breastfeeding

  • Research suggests that maternal Body Mass Index (BMI) can influence breastfeeding practice in quality and duration 5, 6.
  • One study found that the incidence of breastfeeding was significantly lower in overweight and obese women compared with normal weight women 5.
  • Another study found that maternal BMI had limited negative influence on exclusive direct breastfeeding during the first 4 weeks after discharge, but mothers with BMIs greater than 25 who described their infants as vigorous breastfeeders were less likely to exclusively direct breastfeed 6.

Exercise and Breastfeeding Outcomes

  • The studies do not provide conclusive evidence on whether strenuous exercise is harmful or beneficial for breastfeeding mothers with normal BMI 2, 3, 4, 5, 6.
  • However, they suggest that moderate exercise can be beneficial for breastfeeding women, particularly those who are overweight or obese, as it can help with weight loss and improve overall health 2, 3, 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Effect of aerobic and resistive exercise on lipid profile and quality of life in overweight breastfeeding women: A randomized controlled trial.

Physiotherapy research international : the journal for researchers and clinicians in physical therapy, 2024

Research

[Maternal body mass index and breast feeding].

Minerva ginecologica, 2012

Research

Effect of Maternal Body Mass Index on Infant Breastfeeding Behaviors and Exclusive Direct Breastfeeding.

Journal of obstetric, gynecologic, and neonatal nursing : JOGNN, 2015

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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