title: Sitting Time, Physical Activity, and Cardiorespiratory Fitness: Cooper Center Longitudinal Study Cohort.
abstract: BACKGROUND
  Prolonged sitting time is associated with numerous health outcomes; however, the role of cardiorespiratory fitness (CRF) in these relationships is largely unexplored. The cross-sectional association between reported sitting time and measured CRF was examined in a large study of healthy men and women.
  
  
  METHODS
  The analytic sample included 4658 men and 1737 women enrolled in the Cooper Center Longitudinal Study. Unadjusted and adjusted multivariable linear regression models were constructed to examine the association between sitting time and CRF, stratified by sex and meeting (or not) meeting physical activity (PA) guidelines.
  
  
  RESULTS
  In men, CRF was not associated with sitting time after adjustment for potential confounders. In contrast, for women, after adjustment there was a significant association between increased sitting time and lower CRF (P for trend <.001). When stratified by meeting or not meeting PA guidelines, there was no association between sitting time and CRF in men. In women, this relationship was statistically significant regardless of PA category (both P for trend < .05).
  
  
  CONCLUSIONS
  These results suggest that the association between sitting time and CRF varies by sex. Further, meeting PA guidelines does not appear to modify this relation in either sex.
authors.affiliation: The Cooper Institute, Dallas, TX.
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Barlow
authors.forename: Kerem
authors.initials: K
authors.lastname: Shuval
authors.forename: Bijal A
authors.initials: BA
authors.lastname: Balasubramanian
authors.forename: Darla E
authors.initials: DE
authors.lastname: Kendzor
authors.forename: Kelley
authors.initials: K
authors.lastname: Pettee Gabriel
mesh_terms: D015331:Cohort Studies; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D057185:Sedentary Behavior