Purpose: This study aimed to compare 24-h and postprandial glucose responses to incremental intervals of standing (STAND), walking (WALK), and cycling (CYCLE) to a sit-only (SIT) condition.
Methods: Nine overweight/obese (body mass index = 29 ± 3 kg·m−2) adults (30 ± 15 yr) participated in this randomized crossover full-factorial study, with each condition performed 1 wk apart. STAND, CYCLE, and WALK intervals increased from 10 to 30 min·h−1 (2.5 h total) during an 8-h workday. WALK (1.0 mph) and STAND were matched for upright time, and WALK and CYCLE were matched for energy expenditure (~2 METs). Continuous interstitial glucose monitoring was performed for 24 h to include the 8-h workday (LAB), after-work evening hours (EVE), and sleep (SLEEP). Three 2-h postprandial periods were also analyzed. Linear mixed models were used to test for condition differences.
Results: Compared with SIT (5.7 ± 1.0 mmol·L-1), mean 24-h glucose during STAND (5.4 ± 0.9 mmol·L−1) and WALK (5.3 ± 0.9 mmol·L−1) were lower, and CYCLE (5.1 ± 1.0 mmol·L−1) was lower than all other conditions (all P < 0.001). During LAB and EVE, mean glucose was lower for STAND, WALK, and CYCLE compared with SIT (P < 0.001). During SLEEP, the mean glucose for CYCLE was lower than all other conditions (P < 0.001). Compared with SIT, cumulative 6-h postprandial mean glucose was 5%–12% lower (P < 0.001) during STAND, WALK, and CYCLE, and 6-h postprandial glucose integrated area under the curve was 24% lower during WALK (P < 0.05) and 44% lower during CYCLE (P < 0.001).
Conclusions: Replacing sitting with regular intervals of standing or light-intensity activity during an 8-h workday reduces 24-h and postprandial glucose. These effects persist during evening hours, with CYCLE having the largest and most sustained effect.
School of Nutrition and Health Promotion, Arizona State University, Phoenix, AZ
Address for correspondence: Glenn Gaesser, Ph.D., School of Nutrition and Health Promotion, Arizona State University, 550 N 3rd Street; E-mail; email@example.com.
Submitted for publication December 2015.
Accepted for publication July 2016.