The effect of frequency of activity interruptions in prolonged sitting on postprandial glucose metabolism: A randomized crossover trial.
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/m2; VO2max*, 39.5 (38.8; 40.9) ml/min/kg; HbA1c, 5.3 ± 0.4% (34.1 ± 4.2 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 included 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/l∗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.
['Thorsen|Ida K|IK|', 'Johansen|Mette Y|MY|', 'Pilmark|Nanna S|NS|', 'Jespersen|Naja Z|NZ|', 'Brinkløv|Cecilie F|CF|', 'Benatti|Fabiana B|FB|', 'Dunstan|David W|DW|', 'Karstoft|Kristian|K|', 'Pedersen|Bente K|BK|', 'Ried-Larsen|Mathias|M|']
D000328:Adult D015308:Anaerobic Threshold D001786:Blood Glucose D015992:Body Mass Index D002096:C-Peptide D018592:Cross-Over Studies D015444:Exercise D006442:Glycated Hemoglobin A D006801:Humans D007328:Insulin D008297:Male D008875:Middle Aged D056128:Obesity, Abdominal D019518:Postprandial Period D057185:Sedentary Behavior D000077708:Sitting Position D016138:Walking D055815:Young Adult
Postprandial glucose metabolism Walking Cardiometabolic risk Postprandial lipid metabolism Sedentary behavior Substrate oxidation