Assessing SB as a sum of behaviours and using a previous day recall were the most promising features of existing tools .
Accuracy was poor for all existing tools , with underestimation and overestimation of SB .
There was a lack of evidence about sensitivity to change .
OBJECTIVE Sedentary behaviour ( SB ) has distinct deleterious health outcomes , yet there is no consensus on best practice for measurement .
This study aim ed to identify the optimal self-report tool for population surveillance of SB , using a systematic framework .
Leisure time spent sitting in relation to total mortality in a prospective cohort of US adults.
The obesity epidemic is attributed in part to reduced physical activity . Evidence supports that reducing time spent sitting , regardless of activity , may improve the metabolic consequences of obesity . Analyses were conducted in a large prospect i ve study of US adults enrolled by the American Cancer Society to examine leisure time spent sitting and physical activity in relation to mortality .  Time spent sitting and physical activity were queried by question naire on 53,440 men and 69,776 women who were disease free at enrollment . The authors identified 11,307 deaths in men and 7,923 deaths in women during the 14-year follow-up . After adjustment for smoking , body mass index , and other factors , time spent sitting ( > or = 6 vs. <3 hours/day ) was associated with mortality in both women ( relative risk = 1.34 , 95 % confidence interval ( CI ) : 1.25 , 1.44 ) and men ( relative risk = 1.17 , 95 % CI : 1.11 , 1.24 ) . Relative risks for  sitting  ( > or = 6 hours/day ) and  physical activity  ( < 24.5 metabolic equivalent (MET)-hours/week ) combined were 1.94 ( 95 % CI : 1.70 , 2.20 ) for women and 1.48 ( 95 % CI : 1.33 , 1.65 ) for men , compared with those with the least time sitting and most activity . Associations were strongest for cardiovascular disease mortality . The time spent sitting was independently associated with total mortality , regardless of physical activity level . Public health messages should include both being physically active and reducing time spent sitting
Assessing SB as a sum of behaviours and using a previous day recall were the most promising features of existing tools .
Accuracy was poor for all existing tools , with underestimation and overestimation of SB .
There was a lack of evidence about sensitivity to change .
OBJECTIVE Sedentary behaviour ( SB ) has distinct deleterious health outcomes , yet there is no consensus on best practice for measurement .
This study aim ed to identify the optimal self-report tool for population surveillance of SB , using a systematic framework .