title: Physical activity/fitness peaks during perimenopause and BMI change patterns are not associated with baseline activity/fitness in women: a longitudinal study with a median 7-year follow-up.
abstract: OBJECTIVE
  To assess the age-associated longitudinal trends in cardiorespiratory fitness (CRF), leisure-time physical activity (PA), and body mass index (BMI) across the lifespan in a cohort of adult women.
  
  
  METHODS
  The sample included 1467 women from the Aerobics Center Longitudinal Study who were 30-79 years old at baseline and had 3-22 health examinations between 1971 and 2006. CRF was quantified by maximal Balke treadmill exercise tests. The total metabolic equivalent-minutes/week of self-reported PA and measured BMI (kg/m(2)) were calculated.
  
  
  RESULTS
  The overall pattern of CRF decreased over time. After age 60 years, fitness level tended to decline rapidly. Women at age 50 had the highest PA level, which decreased after age 50 and plateaued at age 60. The overall pattern of BMI increased with age. However, after age 60 years the rate of increase in BMI became much slower. Adjusting for smoking, health status, and the individual exposures of CRF, PA and BMI did not influence the observed associations. Women who did not meet current PA recommendation or those who were low fit at baseline had a higher BMI throughout adulthood than their more active or fit peers, but the trajectory of BMI was unassociated with baseline activity or fitness levels.
  
  
  CONCLUSIONS
  We concluded that the age-related longitudinal patterns in physical activity and fitness are not linear. Baseline activity and fitness levels are associated with BMI status during adulthood, but do not affect BMI change trajectory.
authors: Department of Exercise Science, University of South Carolina, Arnold School of Public Health, Columbia, South Carolina 29208, USA. msui@mailbox.sc.edu
authors: Xuemei
authors: X
authors: Sui
authors: Jiajia
authors: J
authors: Zhang
authors: Duck-Chul
authors: DC
authors: Lee
authors: Timothy S
authors: TS
authors: Church
authors: Wenbin
authors: W
authors: Lu
authors: Junxiu
authors: J
authors: Liu
authors: Steven N
authors: SN
authors: Blair
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D015992:Body Mass Index; D002320:Cardiovascular Physiological Phenomena; D015444:Exercise / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007899:Leisure Activities; D008875:Middle Aged; D047648:Perimenopause / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*