Mortality Risk Reductions for Replacing Sedentary Time With Physical Activities.

Area of Science:

• Public Health
• Epidemiology
• Preventive Medicine

Background:

• Excessive sitting is a known risk factor for premature mortality.
• Sedentary behaviors may displace essential physical activity.

Purpose of the Study:

• To investigate the mortality risk reductions associated with substituting 30 minutes of daily sitting time with light or moderate-to-vigorous physical activity (MVPA).

Main Methods:

• Observational study using data from 37,924 men and 54,617 women in the Cancer Prevention Study-II Nutrition Cohort.
• Isotemporal substitution approach with Cox proportional hazards regression to estimate mortality risk.
• Analyses adjusted for potential confounders and were conducted in 2018.

Main Results:

• Among the least active, replacing 30 minutes of sitting with light activity reduced mortality risk by 14%; replacement with MVPA reduced risk by 45%.
• Moderately active individuals also showed risk reductions with activity substitution.
• No significant mortality risk reduction was observed for the most active individuals when substituting sitting time with light activity or MVPA.

Conclusions:

• Replacing even modest amounts of sitting time with light physical activity can potentially lower premature death risk in less active adults.
• The findings underscore the public health importance of reducing sedentary time and increasing physical activity levels across the population.