title: Exercise effect on oxidative stress is independent of change in estrogen metabolism.
abstract: OBJECTIVE
  The effect of exercise training on lipid peroxidation and endogenous estrogens is not well understood in premenopausal women. Exercise effects on these variables could mediate observed associations of exercise with hormonally related cancers, including breast cancer. The purpose of the study is to determine the effect of 15 weeks of aerobic exercise on lipid peroxidation, endogenous estrogens, and body composition in young, healthy eumenorrheic women.
  
  
  METHODS
  Fifteen sedentary premenopausal women (18-25 years) participated. Pre- and post-exercise training urine collection (three 24-h samples) started 48 h after most recent exercise session for analysis of a marker of lipid peroxidation (F(2)-isoprostane) and endogenous estrogens, including 2-hydroxyestrogens, 4-hydroxyestrogens, 16-alpha-hydroxyestrone, and ratios of these metabolites (2:16, 2:4). Body composition was measured by dual-energy X-ray absorptiometry, and F(2)-isoprostanes and estrogens were measured by gas chromatography-mass spectrometry.
  
  
  RESULTS
  Aerobic exercise resulted in a 34% decrease in F(2)-isoprostane (P = 0.02), a 10% increase in fitness (P = 0.004), a 1.2 kg decrease in body mass (P = 0.007), and a 1.8 kg decrease in fat mass (P = 0.04). No significant changes were noted in estrogens.
  
  
  CONCLUSIONS
  The effect of exercise training on oxidative stress may be relevant to risk for hormonally related cancers.
authors.affiliation: Division of Clinical Epidemiology, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, 423 Guardian Drive, Philadelphia, PA 19104, USA. schmitz@mail.med.upenn.edu
authors.forename: Kathryn H
authors.initials: KH
authors.lastname: Schmitz
authors.forename: Meghan
authors.initials: M
authors.lastname: Warren
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Rundle
authors.forename: Nancy I
authors.initials: NI
authors.lastname: Williams
authors.forename: Myron D
authors.initials: MD
authors.lastname: Gross
authors.forename: Mindy S
authors.initials: MS
authors.lastname: Kurzer
mesh_terms: D000293:Adolescent; D000328:Adult; D004967:Estrogens / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D015227:Lipid Peroxidation; D018384:Oxidative Stress / Q000502:physiology*; D017698:Postmenopause; D017697:Premenopause
chemical_list: D004967:Estrogens