title: Volume and intensity of physical activity in a large population-based cohort of middle-aged and older Australians: prospective relationships with weight gain, and physical function.
abstract: OBJECTIVE
  To examine prospectively whether higher proportions of vigorous physical activity (VPA), independent of total activity volume, are associated with better outcomes in weight maintenance and physical function.
  
  
  METHODS
  We used three-year longitudinal data (2006/07-2009/10) of adults 45 and older (n=32,087; 59.5±9.3years) from New South Wales, Australia. Logistic regression models examined odds of weight gain and functional decline by volume and intensity of physical activity.
  
  
  RESULTS
  On average, body weight increased by 0.66kg (SD=5.83, p<0.001); a validated physical function score (MOS-PF) decreased by 4.79 (SD=12.56, p<0.001). There was a 10% reduction in the odds of weight gain for participants who reported 300min/week or more of moderate to vigorous physical activity (MVPA) compared to less than 150min of MVPA. The proportion of MVPA that was vigorous was not associated with weight change. With the physical functioning outcome, there were independent protective effects from volume and intensity of physical activity. Independent of total MVPA, each 1% increase in the proportion of total activity that was vigorous was associated with a 0.3% decrease in the odds of decline in physical function.
  
  
  CONCLUSIONS
  These prospective findings indicate that VPA per se plays an important role in the prevention of functional decline.
authors.affiliation: Prevention Research Collaboration, Sydney School of Public Health, University of Sydney, Sydney, New South Wales, Australia; Centre for Chronic Disease Prevention, School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Cairns, Queensland, Australia. Electronic address: klaus.gebel@jcu.edu.au.
authors.forename: Klaus
authors.initials: K
authors.lastname: Gebel
authors.affiliation: Prevention Research Collaboration, Sydney School of Public Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Ding
authors.initials: D
authors.lastname: Ding
authors.affiliation: Prevention Research Collaboration, Sydney School of Public Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Adrian E
authors.initials: AE
authors.lastname: Bauman
mesh_terms: D000203:Activities of Daily Living; D000428:Alcohol Drinking / Q000453:epidemiology / Q000523:psychology; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D015438:Health Behavior; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009517:New South Wales / Q000453:epidemiology; D017063:Outcome Assessment, Health Care; D005082:Physical Exertion / Q000502:physiology; D011159:Population Surveillance; D011446:Prospective Studies; D012307:Risk Factors; D057185:Sedentary Behavior; D057566:Self Report; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D013997:Time Factors; D015430:Weight Gain / Q000502:physiology*
keywords: Aging; Physical activity; Physical function; Prospective studies; Weight gain