title: Fitness level and risk of weight gain in middle-age women: a prospective cohort study.
abstract: BACKGROUND
  This study was conducted to determine if cardiorespiratory fitness at baseline, and changes in fitness, influence risk of weight gain (>or= 3 kg) over 20 months. Another aim was to ascertain if potential confounding factors, including age, education, strength training, energy intake, and weight, influence risk of weight gain.
  
  
  METHODS
  In a prospective study of 257 women, fitness (VO(2max)) was assessed using a graded, maximal treadmill test at baseline and follow-up. Energy intake was measured using 7-day, weighed food records. Subjects were divided into quartiles based on fitness. Risk ratios were used to show the risk of weight gain among those who were fit at baseline compared with their counterparts.
  
  
  RESULTS
  Most women gained weight and 23% gained >or= 3 kg. Mean VO(2max) was 35.7 +/- 7.2 mL * kg(-1) * min(-1). Women with low-fitness at baseline had 3.18 times (95% CI: 1.46 to 6.93) greater risk, and moderately fit women had 2.24 times (95% CI: 1.04 to 4.82) greater risk of weight gain than women in the high-fitness quartile. Adjusting for potential confounders had little effect on results.
  
  
  CONCLUSIONS
  High levels of fitness seem to help protect middle-aged women against weight gain, whereas low and moderate fitness increase risk of weight gain over time.
authors.affiliation: Dept of Exercise Sciences, Brigham Young University, Provo, UT, USA.
authors.forename: Larry
authors.initials: L
authors.lastname: Tucker
authors.forename: Travis
authors.initials: T
authors.lastname: Peterson
mesh_terms: D000328:Adult; D000367:Age Factors; D016001:Confidence Intervals; D015930:Diet Records; D002149:Energy Intake; D005080:Exercise Test; D005260:Female; D006304:Health Status; D006339:Heart Rate; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D010101:Oxygen Consumption; D010809:Physical Fitness; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors; D013997:Time Factors; D015430:Weight Gain