Effects Of Interrupting Sitting With Walking Only Or Combined With Resistance Activities On Glycemic Responses

Abstract

PURPOSE: To examine whether interrupting prolonged sitting with brief bouts of walking only or combined with simple resistance activity improve glucose levels in healthy, sedentary, young adults. METHODS: This study included 16 healthy, sedentary adults (9 women; 23.7±2.3 y; BMI 20.8±4.1 kg/m2; VO2max 39.1±5.3 ml·kg-1·min-1) who completed three 26-h laboratory conditions, including 22.5 h in a whole-room calorimeter, separated by 5-14 day washout period. The same procedures were performed in each of the three conditions except for the following 9-h activity period: uninterrupted sitting time (SIT); sitting with 8 min intermittent, brisk (60% VO2max) walking bouts (WALK; 7 bouts for a total of 56 min); or alternating 8-min brisk walks and simple resistance activities (RESIST; 3 bouts of walking and 4 bouts of resistance for a total of 56 min). Continuous glucose monitoring (CGM) was performed for 26 h. Standardized meals were consumed during each condition. The incremental areas under the curve (iAUC) for glucose during the entire observation period and the three segmentation periods (activity, evening, and sleep periods) were compared between conditions after adjustment for standard covariates (e.g., age, sex, et al.) and additional adjustment for energy expenditure (EE). RESULTS: Compared with SIT, RESIST reduced 26-iAUC for CGM by 3.04 mmol·L-1·h [95%CI 0.94-6.33] (p = 0.046). Compared with SIT, WALK and RESIST reduced the CGM iAUC by 3.80 mmol·L-1·h [0.19-7.40] (p = 0.036) and 7.37 mmol·L-1·h [4.08-10.66] (p <0.001) during the 9 h activity period, respectively. The iAUC was lowered by 3.57 mmol·L-1·h [0.06-7.08] (p = 0.045) in RESIST compared to WALK. Upon adjusting for EE, the only effect that remained was the comparison between RESIST and SIT during the activity period. During the evening period, WALK increased the CGM iAUC by 1.91 mmol·L-1·h [0.29-3.54] (p = 0.019) when compared to SIT, this effect was lost after adjustment for EE. CONCLUSIONS: Interrupting 9 h of prolonged sitting time with either WALK or RESIST reduced acute glucose responses in healthy, sedentary adults. This effect was more pronounced in RESIST than WALK and was only maintained during the 26-h period in RESIST. Supported by Shanghai Science and Technology Committee (NO. 16080503300)