Effects of Breaking Sitting by Standing and Acute Exercise on Postprandial Oxidative Stress

Sedentary behavior, which includes sitting and TV viewing, has been identified as an independent risk factor for type 2 diabetes and cardiovascular disease. Breaking sedentary behavior improves metabolic health such as postprandial glycaemia and insulinemia. However, the mechanisms underlying this effect are unclear. Here, we examined whether breaking sitting by standing and acute exercise reduces postprandial oxidative stress. Fifteen participants performed 3 trials (sitting, standing, and exercise), each lasting 2 days, in a randomised order. On day one of sitting trial, participants sat in a chair. For the standing trial, the participants stood 6 times, for a 45-minute period each time. For the exercise trial, the participants walked or ran at approximately 60% of age-predicted maximum heart rate for 30 minutes. On day two of each trial, participants rested and consumed the standardised breakfast and lunch. Blood samples were collected in the morning and afternoon on day one, and fasting and at 2, 4, and 6 hours postprandially on day two. The concentrations of serum derivatives of reactive oxygen metabolites (d-ROMs) measured at 4 hours (P = 0.064) and 6 hours (P = 0.071) tended to be higher than that in the fasting state in the sitting trial, but not standing and exercise trial (two-factor analysis of variance (ANOVA), trial × time interaction, P = 0.006). Our results indicate the importance of reducing sitting time for improving postprandial oxidative stress status