Cardiorespiratory Fitness, Sedentary Time, and Cardiovascular Risk Factor Clustering

JAVAID NAUMAN, DORTHE STENSVOLD, JEFF S. COOMBES, ULRIK WISLØFF

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. Cross-sectional study of 12274 men and 14209 women (≥20 years) without known cardiovascular disease. Self-reported ST measurements during a regular day were divided into three sex specific equally sized groups (≤4, 5-<7, and ≥7h/day). CRF was estimated (eCRF) using a previously validated non-exercise model. Using logistic regression analyses, adjusted odds ratios and 95% confidence intervals (OR (95% CI)) were estimated for the association of ST with CV-RF clustering, and for the potential modifying effect of eCRF. Each hour increase in ST was associated with 5% and 4% greater likelihood of having a CV-RF clustering independent of PA in men and women, respectively. Among participants with higher levels of eCRF, the adjusted ORs associated with ≥7h/day of ST were 0.92 (0.56-1.51) for men, and 1.16 (0.49-2.74) for women, compared with the men and women with low ST (≤4h/day) and high eCRF levels. In combined analyses of eCRF, PA and ST, compared with the reference group of participants meeting the recommendations, ≤4h/day of ST and high eCRF, the ORs were 0.63 (0.27-1.44) and 0.65 (0.14-3.07) in fit men and women with ≥7h/day of ST, and not meeting the recommendations. Men and women meeting the PA recommendations, but being unfit had significantly increased odds of having CV-RF clustering across levels of ST. High levels of eCRF abolished the increased odds of having a clustering of CV-RF associated with high ST, even among those individuals who did not meet current PA recommendations.