Today’s post comes from Mai Chinapaw and Teatske Altenburg. Their lab website can be found here.
A recent commentary by Chinapaw et al. (Prev Med 2014) critically discussed the current evidence on the association between sedentary behaviour and cardiometabolic health in children. The authors conclude that in children, there is no convincing evidence yet on the association between sedentary behaviour and cardiometabolic health. One of the highlighted challenges to advance this field is improving the measurement of sedentary behaviour including total sedentary time and sedentary time accumulated in bouts. Two recent papers examined this important issue.
The first paper (Chinapaw et al., PLoS ONE 2014) aimed to establish evidence-based accelerometer data reduction criteria for assessment of sedentary behaviour patterns in children. This is the first study that examined the influence of data reduction procedures on the number or duration of sedentary bouts in children. The authors formulated the following recommendations: 1) a minimum of 60 minutes of consecutive zeros as the most realistic criterion for non-wear time; and 2) including at least six days with minimum eight valid hours to characterize children’s usual total sedentary time and sedentary time accumulated in bouts, preferably including one weekend day.
The second paper (Altenburg et al., Prev Med 2015) examined occurrence and durations of bouts based on various definitions (bouts of at least 5, 10, 20 or 30 min, allowing 0, 30 or 60 sec >100cpm) in 10-12 year old children. Estimates of sedentary time accumulated in bouts varied largely between the different bout definitions. Generally, children sat mostly in sedentary bouts of at least 5 min, while 20 min bouts were rare. For none of the operational definitions the authors found convincing evidence for a cross-sectional association with cardiometabolic health indicators in 10-12 year old children. However, more significant associations appeared when allowing no tolerance (i.e. zero sec >100cpm). Therefore, the authors recommend that no tolerance should be allowed within a sedentary bout.
Both papers emphasise the need for standardized definitions of sedentary bouts as well as a consensus regarding accelerometer data-reduction criteria to advance the field of sedentary behaviour and the potential associated health risk. Moreover, sedentary behaviour researchers cannot rely on accelerometer data reduction procedures established for assessing physical activity.