title: Estimated change in physical activity level (PAL) and prediction of 5-year weight change in men: the Aerobics Center Longitudinal Study.
abstract: OBJECTIVE
  To determine the relation between the average daily physical activity level (PAL) and the trajectory of weight change in men at risk for weight gain.
  
  
  METHODS
  Clinic-based cohort study over an average of 5 y.
  
  
  METHODS
  Healthy men (N=2501) ages 20-55 y participating in the Aerobics Center Longitudinal Study who had received at least four medical examinations at the Cooper Clinic between 1970 and 1998.
  
  
  METHODS
  Daily leisure-time physical activity was reported and body weight was measured at all four examinations. The average daily PAL (METs 24 h(-1)) was estimated from all activities, as well as from other incidental active and passive activities. Weight change over four examinations was regressed on the change in PAL between the first and third examinations.
  
  
  RESULTS
  Random coefficient regression modeling indicated a curvilinear slope for weight gain over the follow-up among those maintaining the same PAL between the first and third examinations. Weight gain was further accelerated among men who decreased their activity. A shift from a low PAL (<1.45 METs 24 h(-1)) to a moderate (1.45-1.60 METs 24 h(-1)) or high (>1.60 METs 24 h(-1)) PAL was necessary for weight loss over time. Men with initially the lowest PAL had the greatest benefit from increasing activity.
  
  
  CONCLUSIONS
  Daily PAL was inversely related to weight gain in this cohort. Increasing to or maintaining a daily PAL at least 60% above the resting metabolic rate (ie, PAL >1.60 METs 24 h(-1)) may be necessary to maintain body weight in middle-age and can be achieved by incorporating 45-60 min of brisk walking, gardening/yardwork, or cycling into the daily routine.
authors.affiliation: The John B. Pierce Laboratory, Yale University School of Medicine, New Haven, CT 06519, USA. ldipietro@jbpierce.org
authors.forename: L
authors.initials: L
authors.lastname: Di Pietro
authors.forename: J
authors.initials: J
authors.lastname: Dziura
authors.forename: S N
authors.initials: SN
authors.lastname: Blair
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology*; D001835:Body Weight / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007899:Leisure Activities; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D015430:Weight Gain / Q000502:physiology