Breast milk composition after exercise of different intensities

Area of Science:

• Exercise Physiology
• Human Lactation
• Biochemistry

Background:

• Breast milk composition is crucial for infant nutrition.
• The impact of maternal exercise intensity on breast milk is not fully understood.
• Lactic acid (LA) is a metabolite that may be affected by exercise.

Purpose of the Study:

• To investigate changes in breast milk composition following exercise at varying intensities.
• To determine if lactic acid (LA) levels in breast milk are affected by maternal exercise.

Main Methods:

• Nine postpartum women participated in exercise sessions at 50%, 75%, and 100% of VO2max, plus a control.
• Breast milk and blood samples were collected pre-exercise and at multiple time points post-exercise.
• Samples were analyzed for lactic acid (LA), pH, lipids, ammonium, and urea.

Main Results:

• Breast milk LA significantly increased after 100% VO2max exercise, persisting for 90 minutes.
• No significant changes in breast milk LA were observed after 50% or 75% VO2max exercise.
• Milk pH, lipid, ammonium, and urea levels remained unchanged across all exercise intensities.

Conclusions:

• Moderate-intensity exercise (50-75% VO2max) does not significantly alter breast milk composition.
• High-intensity exercise (100% VO2max) transiently elevates breast milk lactic acid.
• Lactating mothers can engage in moderate exercise without concern for detrimental changes in breast milk quality.