Breaking up prolonged sitting reduces postprandial glucose and insulin responses

OBJECTIVEdObservational studies show breaking up prolonged sitting has beneficial asso-ciations with cardiometabolic risk markers, but intervention studies are required to investigate causality. We examined the acute effects on postprandial glucose and insulin levels of uninter-rupted sitting compared with sitting interrupted by brief bouts of light- or moderate-intensity walking. RESEARCHDESIGNANDMETHODSdOverweight/obese adults (n = 19), aged 45–65 years, were recruited for a randomized three-period, three-treatment acute crossover trial: 1) uninterrupted sitting; 2) seated with 2-min bouts of light-intensity walking every 20 min; and 3) seated with 2-min bouts of moderate-intensity walking every 20 min. A standardized test drink was provided after an initial 2-h period of uninterrupted sitting. The positive incremental area under curves (iAUC) for glucose and insulin (mean [95%CI]) for the 5 h after the test drink (75 g glucose, 50 g fat) were calculated for the respective treatments. RESULTSdThe glucose iAUC (mmol/L) z h after both activity-break conditions was reduced (light: 5.2 [4.1–6.6]; moderate: 4.9 [3.8–6.1]; both P, 0.01) compared with uninterrupted sitting (6.9 [5.5–8.7]). Insulin iAUC (pmol/L) z h was also reduced with both activity-break conditions (light: 633.6 [552.4–727.1]; moderate: 637.6 [555.5–731.9], P, 0.0001) compared with uninterrupted sitting (828.6 [722.0–950.9]). CONCLUSIONSdInterrupting sitting time with short bouts of light- or moderate-intensity walking lowers postprandial glucose and insulin levels in overweight/obese adults. This may improve glucose metabolism and potentially be an important public health and clinical inter-vention strategy for reducing cardiovascular risk. Diabetes Care 35:976–983, 2012 P rolonged sitting time is associatedwith premature cardiovascular andall-cause mortality, independent of leisure-time physical activity and adiposity (1,2). Findings from the 2003–2004 an