Postpartum Exercise Promotes Maternal-Infant Molecular Communication via Breast Milk Small Extracellular Vesicles

Summary

This study demonstrates that a single session of moderate-intensity postpartum aerobic exercise increases the concentration and metabolic cargo of small extracellular vesicles (sEVs) in human breast milk, with effects persisting across multiple subsequent milk collections. The exercise-enriched sEVs contain regulatory molecules (proteins, miRNAs, metabolites) that enhance mitochondrial respiration capacity in neonatal-stage cells, suggesting a mechanistic link between maternal postpartum physical activity and beneficial infant metabolic programming via milk-borne signalling. The findings characterise sEVs as an exercise-responsive molecular compartment mediating maternal–infant communication through breast milk.

Regional applicability

This laboratory study was conducted in the United States (inferred from author affiliations and publication context) and has direct clinical relevance to postpartum maternal and infant health globally, including in United Kingdom practice. The findings could inform postpartum exercise recommendations for lactating women in the UK, though translation to clinical guidance would require validation of the metabolic benefits in living infants and assessment of dose–response effects across diverse populations.

Key measures

Breast milk sEV concentration; sEV protein, miRNA, and metabolite composition; mitochondrial respiration capacity in UC-MSCs (umbilical cord mesenchymal stem cells); temporal persistence of exercise-induced sEV changes across multiple milk expressions

Outcomes reported

The study measured breast milk small extracellular vesicle (sEV) concentration and composition following acute postpartum aerobic exercise, and assessed the metabolic effects of exercise-enriched sEVs on neonatal-stage cells. A single moderate-intensity exercise session robustly increased sEV concentration persisting across multiple milk collections, with enriched metabolic cargo (proteins, miRNAs, metabolites) enhancing mitochondrial respiration in umbilical cord mesenchymal stem cells.

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