title: Vigorous physical activity and longitudinal associations with cardiometabolic risk factors in youth.
abstract: OBJECTIVE
  To examine the longitudinal associations between different physical activity (PA) intensities and cardiometabolic risk factors among a sample of Canadian youth.
  
  
  METHODS
  The findings are based on a 2-year prospective cohort study in a convenience sample of 315 youth aged 9-15 years at baseline from rural and urban schools in Alberta, Canada. Different intensities (light, moderate and vigorous) of PA were objectively assessed with Actical accelerometers. The main outcome measures were body mass index (BMI) z-score, waist circumference, cardiorespiratory fitness and systolic blood pressure at 2-year-follow-up and conditional BMI z-score velocity. A series of linear regression models were conducted to investigate the associations after adjusting for potential confounders.
  
  
  RESULTS
  At follow-up, cardiorespiratory fitness increased (quartile 1 vs quartile 4=43.3 vs 50.2; P(trend)<0.01) and waist circumference decreased (quartile 1 vs quartile 4=79.0 vs 72.6; P(trend)=0.04; boys only) in a dose-response manner across quartiles of baseline vigorous-intensity PA. A similar trend was observed for systolic blood pressure (quartile 1 vs quartile 4=121.8 vs 115.3; P(trend)=0.07; boys only). Compared with quartile 1 of vigorous-intensity PA, BMI z-score at follow-up and conditional BMI z-score velocity were significantly lower in the quartile 2 and 3 (P<0.05). Waist circumference at follow-up also decreased (quartile 1 vs quartile 4=75.3 vs 73.8; P(trend)=0.04) across quartiles of baseline moderate-intensity PA.
  
  
  CONCLUSIONS
  Time spent in vigorous-intensity PA was associated with several positive health outcomes 2 years later. These findings suggest that high-intensity activities in youth help to reduce the risk for several chronic diseases.
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: V
authors.initials: V
authors.lastname: Carson
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: R L
authors.initials: RL
authors.lastname: Rinaldi
authors.affiliation: Ever Active Schools, Edmonton, Alberta, Canada.
authors.forename: B
authors.initials: B
authors.lastname: Torrance
authors.affiliation: School of Public Health, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Maximova
authors.affiliation: Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: G D C
authors.initials: GD
authors.lastname: Ball
authors.affiliation: 1] School of Public Health, University of Alberta, Edmonton, Alberta, Canada [2] Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: S R
authors.initials: SR
authors.lastname: Majumdar
authors.affiliation: Priority Research Centre in Physical Activity and Nutrition, The University of Newcastle, Newcastle, New South Wales, Australia.
authors.forename: R C
authors.initials: RC
authors.lastname: Plotnikoff
authors.affiliation: School of Public Health, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Veugelers
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: N G
authors.initials: NG
authors.lastname: Boulé
authors.affiliation: Black Gold Regional Schools, Leduc, Alberta, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Wozny
authors.affiliation: Faculty of Agricultural, Life and Environmental Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: L
authors.initials: L
authors.lastname: McCargar
authors.affiliation: Menzies Centre for Health Policy, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Downs
authors.affiliation: Manitoba Institute of Child Health, Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Daymont
authors.affiliation: Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Lewanczuk
authors.affiliation: Manitoba Institute of Child Health, Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: J
authors.initials: J
authors.lastname: McGavock
mesh_terms: D061725:Accelerometry / Q000379:methods; D000293:Adolescent; D000416:Alberta; D001794:Blood Pressure; D001823:Body Composition; D015992:Body Mass Index; D002170:Canada; D002318:Cardiovascular Diseases / Q000209:etiology / Q000517:prevention & control*; D002648:Child; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008297:Male; D008659:Metabolic Diseases / Q000209:etiology / Q000517:prevention & control*; D063766:Pediatric Obesity / Q000150:complications / Q000517:prevention & control*; D010809:Physical Fitness; D011446:Prospective Studies; D012307:Risk Factors; D012572:School Health Services; D017678:Sex Distribution; D013997:Time Factors