title: Outdoor time is associated with physical activity, sedentary time, and cardiorespiratory fitness in youth.
abstract: OBJECTIVE
  To determine whether time spent outdoors was associated with increased moderate-to-vigorous physical activity (MVPA) and related health benefits in youth.
  
  
  METHODS
  We performed a cross-sectional study of 306 youth aged 13.6 ± 1.4 years. The exposure of interest was self-reported time spent outdoors after school, stratified into three categories: none, some, and most/all of the time. The main outcome of interest was accelerometer-derived MVPA (Actical: 1500 to >6500 counts/min). Secondary outcomes included sedentary behavior, cardiorespiratory fitness, overweight status, and blood pressure.
  
  
  RESULTS
  Among the 306 youth studied, those who reported spending most/all of their after-school time outdoors (n = 120) participated in more MVPA (61.0 ± 24.3 vs 39.9 ± 19.1 min/day; adjusted P < .001), were more likely to achieve the recommended minimum 60 min/day of MVPA (aOR 2.8; 95% CI, 1.3-6.4), spent less time in sedentary activities (539 ± 97 min/day vs 610 ± 146 min/day; adjusted P < .001), and had higher cardiorespiratory fitness (49 ± 5 vs 45 ± 6 mL/kg/min; adjusted P < .001) than youth who reported no time outdoors (n = 52). No differences in overweight/obesity or blood pressure were observed across the groups.
  
  
  CONCLUSIONS
  Time spent outdoors is positively associated with MVPA and cardiorespiratory fitness in youth and negatively associated with sedentary behavior. Experimental trials are needed to determine whether strategies designed to increase time spent outdoors exert a positive influence on physical activity and fitness levels in youth.
authors.affiliation: Faculty of Education, University of Regina, Regina, Saskatchewan, Canada.
authors.forename: Lee
authors.initials: L
authors.lastname: Schaefer
authors.affiliation: Priority Research Center in Physical Activity and Nutrition, The University of Newcastle, Newcastle, New South Wales, Australia.
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Plotnikoff
authors.affiliation: School of Public Health, University of Alberta, Edmonton, Alberta, Canada; Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Sumit R
authors.initials: SR
authors.lastname: Majumdar
authors.affiliation: Department of Pediatrics and Child Health, Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Mollard
authors.affiliation: Department of Pediatrics and Child Health, Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Meaghan
authors.initials: M
authors.lastname: Woo
authors.affiliation: Department of Pediatrics and Child Health, Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Rashik
authors.initials: R
authors.lastname: Sadman
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Randi Lynn
authors.initials: RL
authors.lastname: Rinaldi
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Normand
authors.initials: N
authors.lastname: Boulé
authors.affiliation: Ever Active Schools, Edmonton, Alberta, Canada.
authors.forename: Brian
authors.initials: B
authors.lastname: Torrance
authors.affiliation: Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Geoff D C
authors.initials: GD
authors.lastname: Ball
authors.affiliation: School of Public Health, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Veugelers
authors.affiliation: Black Gold School District, Alberta, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Wozny
authors.affiliation: Faculty of Agricultural, Life and Environmental Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Linda
authors.initials: L
authors.lastname: McCargar
authors.affiliation: Menzies Center for Health Policy, University of Sydney, Sydney, Australia.
authors.forename: Shauna
authors.initials: S
authors.lastname: Downs
authors.affiliation: Department of Pediatrics and Child Health, Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Lewanczuk
authors.affiliation: Faculty of Education, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Douglas
authors.initials: D
authors.lastname: Gleddie
authors.affiliation: Department of Pediatrics and Child Health, Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada. Electronic address: jmcgavock@mich.ca.
authors.forename: Jonathan
authors.initials: J
authors.lastname: McGavock
mesh_terms: D000293:Adolescent; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006321:Heart / Q000502:physiology*; D006801:Humans; D008297:Male; D009043:Motor Activity; D010809:Physical Fitness; D010988:Play and Playthings; D012143:Respiratory Physiological Phenomena; D057185:Sedentary Behavior; D013997:Time Factors