Physical activity can erase mortality risks of sitting

  • J Am Coll Cardiol

  • International Clinical Digest
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Takeaway

  • Sitting is a risk for all-cause and cardiovascular disease (CVD) mortality among the least physically active.
  • Among those who meet recommended targets for moderate-vigorous physical activity, however, the risk is mitigated or erased completely.

Why this matters

  • Accompanying editorial says clinicians can consider how to apply these findings for patients who want to reduce their risk but still have to do a lot of sitting.

Key results

  • Each hour increase in daily sitting increased CVD death in those who were “high sitters” (>8 hours/day: HR, 1.07 [95% CI, 1.03-1.12]).
  • Sitting time showed a dose-response effect on mortality risk.
  • Least sedentary (8 hours/day): all-cause mortality HR, 1.52 (95% CI, 1.13-2.03).
  • Among those meeting physical activity recommendations, evidence was limited for increased risk.
  • If people who sat a lot started walking more, risk decreased.
    • Example: for those sitting 6 hours/day, for every hour they did vigorous physical activity instead, CVD mortality risk dropped: HR, 0.36 (95% CI, 0.17-0.74).

Study design

  • Longitudinal analysis, 45 and Up Study.
  • n=149,077, with a median follow-up of 8.9 years for all-cause mortality, 7.4 years for CVD mortality.
  • Funding: Some author foundation, industry funding cited.

Limitations

  • Exposures measured only at baseline.