Sitting Time, Physical Activity, and Risk of Mortality in Adults

J Am Coll Cardiol. 2019 Apr 30;73(16):2062-2072. doi: 10.1016/j.jacc.2019.02.031.


Background: It is unclear what level of moderate to vigorous intensity physical activity (MVPA) offsets the health risks of sitting.

Objectives: The purpose of this study was to examine the joint and stratified associations of sitting and MVPA with all-cause and cardiovascular disease (CVD) mortality, and to estimate the theoretical effect of replacing sitting time with physical activity, standing, and sleep.

Methods: A longitudinal analysis of the 45 and Up Study calculated the multivariable-adjusted hazard ratios (HRs) of sitting for each sitting-MVPA combination group and within MVPA strata. Isotemporal substitution modeling estimated the per-hour HR effects of replacing sitting.

Results: A total of 8,689 deaths (1,644 due to CVD) occurred among 149,077 participants over an 8.9-year (median) follow-up. There was a statistically significant interaction between sitting and MVPA only for all-cause mortality. Sitting time was associated with both mortality outcomes in a nearly dose-response manner in the least active groups reporting <150 MVPA min/week. For example, among those reporting no MVPA, the all-cause mortality HR comparing the most sedentary (>8 h/day) to the least sedentary (<4 h/day) groups was 1.52 (95% confidence interval: 1.13 to 2.03). There was inconsistent and weak evidence for elevated CVD and all-cause mortality risks with more sitting among those meeting the lower (150 to 299 MVPA min/week) or upper (≥300 MVPA min/week) limits of the MVPA recommendation. Replacing sitting with walking and MVPA showed stronger associations among high sitters (>6 sitting h/day) where, for example, the per-hour CVD mortality HR for sitting replaced with vigorous activity was 0.36 (95% confidence interval: 0.17 to 0.74).

Conclusions: Sitting is associated with all-cause and CVD mortality risk among the least physically active adults; moderate-to-vigorous physical activity doses equivalent to meeting the current recommendations attenuate or effectively eliminate such associations.

Keywords: cardiovascular disease; epidemiology; exercise; mortality; physical activity; sedentary behavior.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Aged
  • Cardiovascular Diseases / etiology
  • Cardiovascular Diseases / mortality*
  • Cardiovascular Diseases / physiopathology
  • Cohort Studies
  • Exercise*
  • Female
  • Humans
  • Kaplan-Meier Estimate
  • Male
  • Middle Aged
  • New South Wales
  • Physical Fitness*
  • Proportional Hazards Models
  • Prospective Studies
  • Risk Assessment
  • Sedentary Behavior
  • Sex Factors
  • Sitting Position*
  • Survival Analysis
  • Time Factors