title: The effect of physical activity across the menstrual cycle on reproductive function.
abstract: OBJECTIVE
  To evaluate the association between physical activity (PA) across the menstrual cycle and reproductive function.
  
  
  METHODS
  The BioCycle Study (2005-2007) followed 259 healthy premenopausal women not using hormonal contraceptives for up to two menstrual cycles (N = 509 cycles). Serum leptin, estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, and testosterone were measured five to eight times per cycle. Linear mixed models were used to estimate the effect of past-week PA (measured four times during each cycle) on hormone levels. Past-week PA was categorized into tertiles based on metabolic equivalent of task hours per week (cut-points were 15.3 and 35.7). Risk ratios for sporadic anovulation were estimated using generalized linear models. Analyses adjusted for habitual PA (assessed at baseline), body mass index, race, age, and perceived stress. Linear mixed models used inverse probability weights to control for concurrent reproductive hormones and caloric intake.
  
  
  RESULTS
  High past-week PA was inversely associated with leptin (-6.6%; 95% confidence interval, -10.6 to -2.5) and luteal phase progesterone (-22.1%; -36.2 to -4.7) as compared with low past-week PA. High past-week PA was not significantly associated with sporadic anovulation (adjusted risk ratio, 1.5; 0.6 to 3.4).
  
  
  CONCLUSIONS
  High levels of PA were modestly associated with changes in select hormones but not sporadic anovulation among moderate to highly active premenopausal women.
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD. Electronic address: katherine.ahrens@nih.gov.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Ahrens
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Vladutiu
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
authors.forename: Sunni L
authors.initials: SL
authors.lastname: Mumford
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
authors.forename: Karen C
authors.initials: KC
authors.lastname: Schliep
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Perkins
authors.affiliation: Department of Social and Preventive Medicine, University at Buffalo, Buffalo, NY.
authors.forename: Jean
authors.initials: J
authors.lastname: Wactawski-Wende
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
authors.forename: Enrique F
authors.initials: EF
authors.lastname: Schisterman
mesh_terms: D000368:Aged; D000858:Anovulation / Q000097:blood / Q000503:physiopathology; D015331:Cohort Studies; D004958:Estradiol / Q000097:blood*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D006801:Humans; D007899:Leisure Activities; D020738:Leptin / Q000097:blood*; D016014:Linear Models; D007986:Luteinizing Hormone / Q000097:blood*; D008597:Menstrual Cycle / Q000097:blood; D008875:Middle Aged; D009043:Motor Activity; D009518:New York; D017697:Premenopause / Q000097:blood; D011374:Progesterone / Q000097:blood*
chemical_list: D020738:Leptin; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone
keywords: Hormones; Leisure activity; Menstrual cycle; Motor activity; Women