title: Differences between work and leisure in temporal patterns of objectively measured physical activity among blue-collar workers.
abstract: BACKGROUND
  Leisure time physical activity (LTPA) is generally associated with favorable cardiovascular health outcomes, while occupational physical activity (OPA) shows less clear, or even opposite, cardiovascular effects. This apparent paradox is not sufficiently understood, but differences in temporal patterns of OPA and LTPA have been suggested as one explanation. Our aim was to investigate the extent to which work and leisure (non-occupational time) differ in temporal activity patterns among blue-collar workers, and to assess the modification of these patterns by age and gender.
  
  
  METHODS
  This study was conducted on a cross-sectional sample of male (n = 108) and female (n = 83) blue-collar workers, aged between 21 and 65 years. Physical activity and sedentary behavior were assessed using accelerometers (Actigraph GT3X+) worn on the thigh and trunk for four consecutive days. Temporal patterns of OPA and LTPA were retrieved using Exposure Variation Analysis (EVA), and expressed in terms of percentage of work and leisure time spent in uninterrupted periods of different durations (<1 min, 1-5 min, 5-10 min, 10-30 min, 30-60 min and > 60 min) of sitting, standing, and walking. Repeated measures ANOVA and linear regression analyses were used to test a) possible differences between OPA and LTPA in selected EVA derivatives, and b) the modification of these differences by age and gender.
  
  
  RESULTS
  OPA showed a larger percentage time walking in brief (<5 min) periods [mean (SD): 33.4 % (12.2)], and less time in prolonged (>30 min) sitting [7.0 % (9.3)] than LTPA [walking 15.4 % (5.0); sitting 31.9 % (15.3)], even after adjustment for the difference between work and leisure in total time spent in each activity type. These marked differences in the temporal pattern of OPA and LTPA were modified by gender, but not age.
  
  
  CONCLUSIONS
  We found that the temporal patterns of OPA and LTPA among blue-collar workers were markedly different even after adjustment for total physical activity time, and that this difference was modified by gender. We recommend using EVA derivatives in future studies striving to disentangle the apparent paradoxical cardiovascular effect of physical activity at work and during leisure.
authors.affiliation: Centre for Musculoskeletal Research, Department of Occupational and Public Health Sciences, University of Gävle, Kungsbäcksvägen 47, SE 801 76, Gävle, Sweden. david.hallman@hig.se.
authors.forename: David M
authors.initials: DM
authors.lastname: Hallman
authors.affiliation: Centre for Musculoskeletal Research, Department of Occupational and Public Health Sciences, University of Gävle, Kungsbäcksvägen 47, SE 801 76, Gävle, Sweden. svenderik.mathiassen@hig.se.
authors.forename: Svend Erik
authors.initials: SE
authors.lastname: Mathiassen
authors.affiliation: National Research Centre for the Working Environment, Copenhagen, Denmark. ngu@nrcwe.dk.
authors.forename: Nidhi
authors.initials: N
authors.lastname: Gupta
authors.affiliation: National Research Centre for the Working Environment, Copenhagen, Denmark. mkl@nrcwe.dk.
authors.forename: Mette
authors.initials: M
authors.lastname: Korshøj
authors.affiliation: National Research Centre for the Working Environment, Copenhagen, Denmark. aho@nrcwe.dk.
authors.forename: Andreas
authors.initials: A
authors.lastname: Holtermann
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D007899:Leisure Activities; D008297:Male; D008875:Middle Aged; D016272:Occupational Health; D009790:Occupations / Q000706:statistics & numerical data*; D012737:Sex Factors; D013997:Time Factors; D017132:Workplace / Q000706:statistics & numerical data*