title: Menstrual cycle abnormalities in healthy women with low physical activity. The North-Trøndelag population-based health study.
abstract: BACKGROUND
  Menstrual dysfunctions are often found in athletic women. This study evaluated the association between leisure time physical activity (LTPA) and menstrual function in healthy nonathletic women.
  
  
  METHODS
  During 1984-1986, a population-based health survey (HUNT 1) was conducted in Nord-Trøndelag, Norway, with follow-up (HUNT 2) in 1995-1997. Women < 45 years old in HUNT 2 were included in the current study. LTPA was assessed by questionnaire in HUNT 1 and HUNT 2, and menstrual function by questionnaire in HUNT 2.
  
  
  RESULTS
  Adjusted odds ratios (OR's) for long cycles were increased in women who reported < 1 hour of light LTPA (OR = 1.4, 95% CI = 1.0-2.0) and 1-2 hours (OR = 1.3, 95% CI = 1.0-1.8) per week compared with women with ≥ 3 hours/week. Adjusted OR for irregular cycles was decreased in women constantly in the lowest tertile of LTPA index in HUNT 1 and HUNT 2 (OR = 0.4, 95% CI = 0.2-0.9). Adjusted OR for prolonged bleeding was 2.6 (95% CI = 1.3-5.4) for women with < 1 hour/week of light LTPA and 2.3 (95% CI = 1.3-4.3) for women with 1-2 hours, compared with ≥ 3 hours/week.
  
  
  CONCLUSIONS
  Very low physical activity may increase the risk of menstrual cycle disruptions. Moderate PA should be encouraged for optimum reproductive health.
authors: Dept of Human Movement Science, Norwegian University of Science and Technology, Trondheim, Norway.
authors: Sigridur Lara
authors: SL
authors: Gudmundsdottir
authors: W Dana
authors: WD
authors: Flanders
authors: Liv Berit
authors: LB
authors: Augestad
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D008597:Menstrual Cycle; D008599:Menstruation Disturbances / Q000453:epidemiology* / Q000209:etiology*; D009043:Motor Activity; D009664:Norway; D016017:Odds Ratio; D012306:Risk; D057185:Sedentary Behavior; D011795:Surveys and Questionnaires; D055815:Young Adult