Sedentary Time and Television Viewing Time Are Associated with an Increased Risk for All-Cause Mortality: A Systematic Review of Systematic Reviews.

OBJECTIVES:This umbrella review tested the hypothesis that increased sedentary time and behaviours (e.g., television viewing) would be associated with increased risk in all-cause mortality, even when accounting for physical activity and measured using device-based and self-report measures. METHODS:Reviews were included if they conducted a systematic review and/or meta-analysis on the impact of sedentary time/behaviours on all-cause mortality in adults. Sources were searched from inception-March 2025 and included Scopus, EMBASE, MEDLINE, CINAHL, and Academic Search Premier with no date restrictions applied. The Joanna Briggs Institute and Risk of Bias in Systematic Reviews tools assessed study quality and PRISMA reporting were followed. RESULTS:Thirty reviews (n = 83 unique studies, n = 2,778,595 unique participants) were included and investigated total sedentary time (n = 28, meta-analyses n = 17) and television viewing time (n = 7, meta-analyses n = 7). Average study quality was 9.6 ± 1.6/11.0. n = 29/30 observed a positive relationship between sedentary time or television viewing time with all-cause mortality. Results remained significant but were attenuated after accounting for physical activity. Results were consistent across studies using self-report and device-based sedentary measures. CONCLUSION:This umbrella review of high-quality reviews provides evidence that increased sedentary time and television viewing represent a unique risk for all-cause mortality, even when accounting for physical activity.