Breaking up prolonged sitting with light-intensity walking improves postprandial glycemia, but breaking up sitting with standing does not

Objectives: To explore the effects of breaking up prolonged sitting time with standing or light-intensity walking on a range of cardiometabolic risk markers. Design: A randomised three-period, three-treatment acute crossover trial. Methods: Ten non-obese adults took part in three trials: (1) uninterrupted sitting; (2) seated with 2-min bouts of standing every 20 min; and (3) seated with 2-min bouts of light-intensity walking every 20 min. Two standardised test drinks (total 80.3 carbohydrate, 50 g fat) were provided after an initial 1-h period of uninterrupted sitting. Plasma glucose and blood pressure were assessed hourly to calculate area under the curve. Total cholesterol, HDL, and triglycerides were assessed at baseline and 5-h. ANOVAs were used to explore between-trial differences. Results: Glucose area under the curve was lower in the activity-break condition compared to the uninterrupted sitting and standing-break conditions: mean area under the curve 18.5 (95% CI 17, 20), 22.0 (20.5, 23.5), and 22.2 (20.7, 23.7) mmol L/5-h, respectively, p < 0.001; no difference between uninterrupted sitting and standing-break conditions (p > 0.05). Systolic and diastolic blood pressure area under the curve did not differ significantly between conditions, nor did responses in lipid parameters (p > 0.05). Conclusions: This study suggests that interrupting sitting time with frequent brief bouts of light-intensity activity, but not standing, imparts beneficial postprandial responses that may enhance cardiometabolic health. These findings may have importance in the design of effective interventions to reduce cardiometabolic disease risk.