Replacing 30 minutes of sitting with activity may cut mortality

(HealthDay)—Replacing half an hour of daily sitting time with even light physical activity is associated with a reduction in mortality risk among less active adults, according to a study published online March 21 in the American Journal of Preventive Medicine.

Erika Rees-Punia, Ph.D., from the American Cancer Society in Atlanta, and colleagues examined the mortality risk reductions associated with replacing 30 minutes/day of sitting with an equivalent duration of light or moderate-to-vigorous physical activity (MVPA). The analysis included 37,924 men and 54,617 women participating in the Cancer Prevention Study-II Nutrition Cohort; 14,415 men and 13,358 women died during follow-up (from 1999 to 2014).

The researchers found that among the least active participants (≤17 minutes/day MVPA), the replacement of 30 minutes/day of sitting with light physical activity was associated with a 14 percent mortality risk reduction (hazard ratio [HR], 0.86) and replacement with MVPA was associated with a 45 percent reduction in mortality risk (HR, 0.55). Among moderately active participants, similar associations were seen (light physical activity replacement: HR, 0.94; MVPA replacement: HR, 0.83). Substituting sitting time with light physical activity or MVPA was not associated with a reduction in mortality risk for the most active (MVPA >38 minutes/day; HRs, 1 [95 percent confidence interval, 0.97 to 1.03] and 0.99 [95 percent confidence interval, 0.95 to 1.02], respectively).

"These findings suggest that the replacement of modest amounts of sitting time with even light physical activity may have the potential to reduce the risk of premature death among less active adults," the authors write.