Original Article

International Journal of Obesity (2008) 32, 1685–1693; doi:10.1038/ijo.2008.171; published online 14 October 2008

A prospective examination of children's time spent outdoors, objectively measured physical activity and overweight

V Cleland1, D Crawford1, L A Baur2, C Hume1, A Timperio1 and J Salmon1

  1. 1Centre for Physical Activity and Nutrition Research, Deakin University, 221 Burwood Hwy, Burwood, Victoria, Australia
  2. 2Discipline of Paediatrics and Child Health, University of Sydney, c/- Clinical School, The Children's Hospital at Westmead, Westmead, New South Wales, Australia

Correspondence: Dr V Cleland, Centre for Physical Activity and Nutrition Research, Deakin University, 221 Burwood Hwy, Burwood, Victoria 3125, Australia. E-mail: verity.cleland@deakin.edu.au

Received 5 May 2008; Revised 5 August 2008; Accepted 1 September 2008; Published online 14 October 2008.



Objective: This study aimed to determine whether time spent outdoors was associated with objectively measured physical activity, body mass index (BMI) z-score and overweight in elementary-school aged children, cross-sectionally and prospectively over 3 years.

Methods: Three-year cohort study with data collected during 2001 and 2004. Nineteen randomly selected state elementary schools across Melbourne, Australia. One hundred and eighty eight 5–6-year-old and 360 10–12-year-old children. Baseline parent reports of children's time spent outdoors during warmer and cooler months, on weekdays and weekends. At baseline and follow-up, children's moderate and vigorous physical activity (MVPA) was objectively assessed by accelerometry, and BMI z-score and overweight was calculated from measured height and weight.

Results: Cross-sectionally, each additional hour outdoors on weekdays and weekend days during the cooler months was associated with an extra 27minweek−1 MVPA among older girls, and with an extra 20minweek−1 MVPA among older boys. Longitudinally, more time outdoors on weekends predicted higher MVPA on weekends among older girls and boys (5minweek−1). The prevalence of overweight among older children at follow-up was 27–41% lower among those spending more time outdoors at baseline.

Conclusion: Encouraging 10–12-year-old children to spend more time outdoors may be an effective strategy for increasing physical activity and preventing increases in overweight and obesity. Intervention research investigating the effect of increasing time outdoors on children's physical activity and overweight is warranted.


youth, physical activity, overweight, longitudinal, accelerometer

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