title: Cardiorespiratory Fitness, Sedentary Time, and Cardiovascular Risk Factor Clustering.
abstract: OBJECTIVE
  Prolonged sedentary time (ST) is associated with cardiovascular risk factors (CV-RF) independent of physical activity (PA). Whether a high level of cardiorespiratory fitness (CRF) can modify the deleterious health consequences related to high ST is not known.
  
  
  METHODS
  We performed a cross-sectional study of 12,274 men and 14,209 women (≥20 yr) without known cardiovascular disease. Self-reported ST measurements during a regular day were divided into three sex-specific equally sized groups (≤4, 5 to <7, and ≥7 h·d(-1)). CRF was estimated (eCRF) using a previously validated nonexercise model. Using logistic regression analyses, adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated for the association of ST with CV-RF clustering and for the potential modifying effect of eCRF.
  
  
  RESULTS
  Each hour increase in ST was associated with 5% and 4% greater likelihood of having CV-RF clustering independent of PA in men and women, respectively. Among the participants with higher levels of eCRF, the adjusted OR values associated with ≥7 h·d(-1) of ST were 0.92 (0.56-1.51) for men and 1.16 (0.49-2.74) for women, compared with men and women with low ST (≤4 h·d(-1)) and high eCRF levels. In combined analyses of eCRF, PA, and ST, compared with the reference group of participants meeting the recommendations, ≤4 h·d(-1) of ST and high eCRF, the OR values were 0.63 (0.27-1.44) and 0.65 (0.14-3.07) in fit men and women with ≥7 h·d(-1) of ST, which did not meet the recommendations. Men and women meeting the PA recommendations, but were unfit, had significantly increased odds of having CV-RF clustering across levels of ST.
  
  
  CONCLUSIONS
  High levels of eCRF abolished the increased odds of having CV-RF clustering associated with high ST, even among those individuals who did not meet the current PA recommendations.
authors.affiliation: 1The K.G. Jebsen Center of Exercise in Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, NORWAY; 2Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, NORWAY; 3School of Human Movement Studies, The University of Queensland, St. Lucia, Queensland, AUSTRALIA.
authors.forename: Javaid
authors.initials: J
authors.lastname: Nauman
authors.forename: Dorthe
authors.initials: D
authors.lastname: Stensvold
authors.forename: Jeff S
authors.initials: JS
authors.lastname: Coombes
authors.forename: Ulrik
authors.initials: U
authors.lastname: Wisløff
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000072599:Cardiorespiratory Fitness / Q000502:physiology*; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D057185:Sedentary Behavior; D013997:Time Factors; D055815:Young Adult