The effect of frequency of activity interruptions in prolonged sitting on postprandial glucose metabolism: A randomized crossover trial

Abstract

Objective: The primary objective was to test the hypothesis that increased frequency of interruptions in prolonged sitting reduces postprandial glycemia independent of energy intake and expenditure. Materials/Methods: Healthy, sedentary, centrally obese men (n = 14; age*, 28.2 (23.4; 38.3) years; BMI, 31.9 +/- 6.7 kg/m 2 ; VO(2)max*, 39.5 (38.8; 40.9) ml/min/kg; HbA1c, 53 +/- 0.4% (34.1 +/- 42 mmol/mol); mean +/- SD (*median (25th; 75th percentile)) completed four 8-h interventions in randomized order: 1) uninterrupted sitting (SIT), 2) sitting interrupted by 2 min of walking (-30% of VO2max) every 20th minute (INT20), 3) sitting interrupted by 6 min of walking every hour (INT60), and 4) sitting interrupted by 12 min of walking every second hour (INT120). A standardized test drink was served at the beginning of and 4 h into the intervention (total of 2310 +/- 247 kcal; 50% energy from carbohydrate, 50% energy from fat). Outcomes induded the difference in the 8-h total area under the curve (tAUC) for primarily plasma glucose, and secondarily plasma insulin and C-peptide during INT20, INT60, and INT120 compared to SIT. Results: No difference [95% CI] was observed in the primary outcome, the 8-h tAUC for the plasma glucose, during INT20, INT60, and INT120 compared to SIT ( -65.3 mmol/I*min [ - 256.3 ; 125.7], +53.8 mmol/l*min [ - 143.1; 250.8], and +18.6 mmol/l*min [-172.4; 209.6], respectively). Conclusions: Interrupting sitting with increasing frequency did not reduce the postprandial plasma glucose response to prolonged sitting in healthy, sedentary, centrally obese men.