title: Lactation performance of exercising women.
abstract: To determine whether vigorous exercise affects lactation performance, we compared well-nourished exercising (n = 8) and sedentary (n = 8) women whose infants were 9-24 wk old and exclusively breast-fed. Measurements included resting metabolic rate (RMR); maximum oxygen consumption (VO2max); plasma prolactin, cortisol, insulin, and T3; and body composition. Each subject completed a 3-d record of dietary intake, physical activity, and milk volume (by test weighing) and collected 24-h milk samples. Exercising women differed significantly from control subjects in VO2max (46.4 vs 30.3 mL.kg-1.min-1), percent body fat (21.7 vs 27.9%), total energy expenditure (3169 vs 2398 kcal/d), and energy intake (2739 vs 2051 kcal/d). There was no difference between the groups in plasma hormones or milk energy, lipid, protein, or lactose content. Exercising subjects tended to have higher milk volume (839 vs 776 g/d) and energy output in milk (538 vs 494 kcal/d). Thus, there was no apparent adverse effect of vigorous exercise on lactation performance.
authors.affiliation: Department of Nutrition, University of California, Davis 95616.
authors.forename: C A
authors.initials: CA
authors.lastname: Lovelady
authors.forename: B
authors.initials: B
authors.lastname: Lonnerdal
authors.forename: K G
authors.initials: KG
authors.lastname: Dewey
mesh_terms: D000328:Adult; D000886:Anthropometry; D001481:Basal Metabolism / Q000502:physiology; D001823:Body Composition; D001942:Breast Feeding; D002149:Energy Intake / Q000502:physiology; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D006728:Hormones / Q000097:blood; D006801:Humans; D007774:Lactation / Q000502:physiology*; D008895:Milk, Human / Q000032:analysis*; D010101:Oxygen Consumption
chemical_list: D006728:Hormones