title: Prevalence of physical inactivity and its relation to social class in U.S. adults: results from the Third National Health and Nutrition Examination Survey, 1988-1994.
abstract: OBJECTIVE
  This study examines the prevalence of physical inactivity during leisure time in a national representative sample of U.S. adults.
  
  
  METHODS
  Data were obtained from the Third National Health and Nutrition Examination Survey, conducted between 1988 and 1994. A total of 18,825 adults aged 20 yr and older participated in a home interview where information about physical activity, education, income, occupation, employment, and labor force participation was obtained.
  
  
  RESULTS
  The prevalence of physical inactivity among U.S. adults was 23%, with more women (28%) than men (17%) reporting being inactive during their leisure time. Additionally, inactivity is more common among in social class such as persons who are less educated, living below the poverty line, living in households with income below 20,000 dollars, and who are retired. In every category of social class, women experienced a higher prevalence of physical inactivity than men.
  
  
  CONCLUSIONS
  We conclude that social class is associated with physical inactivity and that more research is needed to better understand the effect that other social and environmental factors have on sedentary behaviors in our society.
authors.affiliation: American University, Department of Health and Fitness, Washington, DC 20016-8037, USA. crespoc@american.edu
authors.forename: C J
authors.initials: CJ
authors.lastname: Crespo
authors.forename: B E
authors.initials: BE
authors.lastname: Ainsworth
authors.forename: S J
authors.initials: SJ
authors.lastname: Keteyian
authors.forename: G W
authors.initials: GW
authors.lastname: Heath
authors.forename: E
authors.initials: E
authors.lastname: Smit
mesh_terms: D000328:Adult; D004522:Educational Status; D004651:Employment; D005260:Female; D006801:Humans; D007182:Income; D007407:Interviews as Topic; D007899:Leisure Activities; D008297:Male; D009790:Occupations; D005082:Physical Exertion; D015995:Prevalence; D012923:Social Class; D014481:United States