title: Relation between higher physical activity and public transit use.
abstract: OBJECTIVE
  We isolated physical activity attributable to transit use to examine issues of substitution between types of physical activity and potential confounding of transit-related walking with other walking.
  
  
  METHODS
  Physical activity and transit use data were collected in 2008 to 2009 from 693 Travel Assessment and Community study participants from King County, Washington, equipped with an accelerometer, a portable Global Positioning System, and a 7-day travel log. Physical activity was classified into transit- and non-transit-related walking and nonwalking time. Analyses compared physical activity by type between transit users and nonusers, between less and more frequent transit users, and between transit and nontransit days for transit users.
  
  
  RESULTS
  Transit users had more daily overall physical activity and more total walking than did nontransit users but did not differ on either non-transit-related walking or nonwalking physical activity. Most frequent transit users had more walking time than least frequent transit users. Higher physical activity levels for transit users were observed only on transit days, with 14.6 minutes (12.4 minutes when adjusted for demographics) of daily physical activity directly linked with transit use.
  
  
  CONCLUSIONS
  Because transit use was directly related to higher physical activity, future research should examine whether substantive increases in transit access and use lead to more physical activity and related health improvements.
authors.affiliation: Brian E. Saelens and Chuan Zhou are with Seattle Children's Research Institute and University of Washington School of Medicine Department of Pediatrics, Seattle. Anne Vernez Moudon, Bumjoon Kang, and Philip M. Hurvitz are with the Urban Form Lab and the College of Built Environments Department of Urban Design and Planning, University of Washington.
authors.forename: Brian E
authors.initials: BE
authors.lastname: Saelens
authors.forename: Anne
authors.initials: A
authors.lastname: Vernez Moudon
authors.forename: Bumjoon
authors.initials: B
authors.lastname: Kang
authors.forename: Philip M
authors.initials: PM
authors.lastname: Hurvitz
authors.forename: Chuan
authors.initials: C
authors.lastname: Zhou
mesh_terms: D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D015444:Exercise; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D008297:Male; D012111:Residence Characteristics / Q000706:statistics & numerical data*; D012737:Sex Factors; D012959:Socioeconomic Factors; D014186:Transportation / Q000706:statistics & numerical data*; D014861:Washington