Alternating work posture improves postprandial glucose response without reducing computer task performance in the early afternoon

Abstract

In the workplace, sit-stand workstations are being installed to reduce excessive sitting time and the consequent risk factors for cardiovascular ailments (e.g., postprandial hyperglycemia). However, a prolonged standing posture also has detrimental effects in terms of musculoskeletal symptoms and work efficiency. We thus investigated whether alternating between a sitting and standing work posture improves postprandial glucose response and computer task performance. Nine healthy young males completed 4 × 20-min computer tasks in the early afternoon (i.e., 30 min after eating lunch) under three different work conditions, had no change in posture (only sitting=the control trial, CON), and engaged in two styles of alternating between sitting and standing every 20 min (sitting → standing → sitting → standing, SIT-STAND; standing → sitting → standing → sitting, STAND-SIT). For the computer tasks, all participants had to subtract a two-digit number from a four-digit number and to input the answer in the answer column on the computer. Task performance was evaluated as the number of achievements and accuracy rate every 20 min. Blood glucose concentration was assessed before, immediately after, 30 min, 52 min, 74 min, 96 min, and 118 min after eating lunch. The number of achievements and accuracy rate did not differ among the three trials. The total area under the curve (AUC) for blood glucose concentration was significantly lower in the SIT-STAND and STAND-SIT trials compared with CON, whereas no significant difference was observed between the SIT-STAND and STAND-SIT trials. In conclusion, alternating between a sitting and standing work posture attenuated postprandial blood glucose accumulation without reducing task performance, irrespective of the order of changes in work posture.

Keywords: Computer subtraction task; Hyperglycemia; Post-lunch time.