Prolonged sitting and markers of cardiometabolic disease risk in children and youth: a randomized crossover study.

Objective: Recent evidence suggests that short bouts of uninterrupted sedentary behavior reduce insulin sensitivity and glucose tolerance while increasing triglyceride levels in both healthy and overweight/obese adults. To date no study has examined the acute impact of uninterrupted sitting in children and youth. The objective of the present study was to determine whether 8 h of uninterrupted sitting increases markers of cardiometabolic disease risk in healthy children and youth, in comparison to 8 h of sitting interrupted by light intensity walk breaks or structured physical activity.

Methods: 11 healthy males and 8 healthy females between the ages of 10 and 14 years experienced 3 conditions in random order: (1) 8 h of uninterrupted sitting (Sedentary); (2) 8 h of sitting interrupted with a 2-min light-intensity walk break every 20 min (Breaks); and (3) 8 h of sitting interrupted with a 2-min light-intensity walk break every 20 min as well as 2×20 min of moderate-intensity physical activity (Breaks+Physical Activity). Insulin, glucose, triglyceride, HDL and LDL cholesterol area under the curve were calculated for each condition.

Results: We observed no significant differences in the area under the curve for any marker of cardiometabolic disease risk across the 3 study conditions (all p>0.09).

Conclusions: These results suggest that in comparison to interrupted sitting or structured physical activity, a single bout of 8 h of uninterrupted sitting does not result in measurable changes in circulating levels of insulin, glucose, or lipids in healthy children and youth.