Exercise is associated with elevated proinflammatory cytokines in human milk.
OBJECTIVE
To explore relationships between self-reported exercise in postpartum women and concentrations of cytokines and secretory immunoglobulin A in their milk.


METHODS
Fifty-eight frozen, unthawed aliquots of human hindmilk were available for analysis from a previous larger study on the influence of lactation on postpartum stress and immunity. The samples were early-morning, hand-expressed, hindmilk that had been collected between 4 and 6 weeks. Milk cytokines were analyzed by a multiplex assay of 20 cytokines, chemokines, and growth factors. Milk secretory immunoglobulin A was analyzed by enzyme-linked immunosorbent assay. Exercise data were extracted from a demographic questionnaire that was used in the original study and approximate metabolic-equivalent tasks assigned to the exercise levels reported. Based on reported frequency of exercise at a particular metabolic-equivalent task, caloric expenditures were calculated for each mother.


RESULTS
With increasing metabolic-equivalent tasks, and thus caloric expenditures, proinflammatory cytokines increased in mothers' milk. Secretory immunoglobulin A concentrations were not affected by mother's exercise.


CONCLUSIONS
There are several possible interpretations for these results. These data are preliminary, and a larger, longitudinal study with a more structured exercise instrument will clarify if recommendations should be made about heavy exercise in the early postpartum months.
Groër
Maureen W
MW
University of South Florida, College of Nursing, Tampa, FL 33612, USA. mgroer@health.usf.edu
Shelton
Melissa M
MM
D000328:Adult; D000704:Analysis of Variance; D018925:Chemokines / Q000032:analysis; D015400:Clinical Nursing Research; D003430:Cross-Sectional Studies; D016207:Cytokines / Q000032:analysis* / Q000276:immunology; D004734:Energy Metabolism / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D015444:Exercise / Q000502:physiology*; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000032:analysis; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000032:analysis* / Q000276:immunology; D007371:Interferon-gamma / Q000032:analysis; D007378:Interleukins / Q000032:analysis; D016014:Linear Models; D016015:Logistic Models; D008895:Milk, Human / Q000737:chemistry* / Q000276:immunology; D010298:Parity; D049590:Postpartum Period / Q000276:immunology / Q000378:metabolism; D011247:Pregnancy; D011795:Surveys and Questionnaires; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D018925:Chemokines; D016207:Cytokines; D007071:Immunoglobulin A, Secretory; D007378:Interleukins; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor