Uninterrupted sitting and its effects on health indicators in children – breaks and bouts what are we talking about?

Purpose: Recently the importance of the pattern in which sedentary time is accumulated rather than total sedentary time has been established. To date, there is no consensus on the optimal definition of sedentary bouts and breaks in children. To build evidence for such definitions, we examined the association of various sedentary bout definitions with indicators of weight status and cardiometabolic health.

Methods: Accelerometer data of 647 European 10-12 year old children were collected in eight European countries as part of the ENERGY cross-sectional survey. We analysed sedentary time in bouts of different durations, i.e. ≥5, 10, 20 and 30 minutes <100cpm, tolerating zero, 30 and 60 sec ≥100cpm within sedentary bouts. Indicators of weight status included weight, waist circumference and BMI. A cardiometabolic risk score was calculated on waist circumference and fasting capillary blood levels of glucose, C-peptide, high-density and low-density cholesterol, and triglycerids. Linear regression analyses were adjusted for age, gender, MVPA time, total wear time and country.

Results: Children spent most of their sedentary time in bouts of short duration (up to 10 min) while sedentary bouts ≥20 min were rare. Total sedentary time was not significantly associated with health indicators. Contrarily, associations of accumulated sedentary time with health indicators became stronger with longer bout duration and less tolerance.

Conclusions: We conclude that especially sitting time accumulated in bouts of uninterrupted sitting may be important for health in children. We, therefore, recommend future studies to focus on sedentary time accumulated in prolonged, uninterrupted sedentary bouts.