Effects of breaking up sedentary time with "chair squats" on postprandial metabolism.
Level 2 - randomized trial
Individual randomized crossover trial
PubMed 30058957 · doi:10.1080/02640414.2018.1500856
What was done
Fourteen adults (11 men, 3 women; mean age 37 ± 16 years, BMI 30.5 ± 3.8 kg/m²) completed two experimental trials in random order. Participants arrived fasted, consumed a standardized breakfast, and consumed an identical lunch 3.5 hours later. During one 6.5-hour trial (SIT), participants sat continuously. During the other trial (SIT/STAND), participants broke up sitting by performing 10 chair squats (sit-to-stand transitions) over 30 seconds every 20 minutes. Expired air and blood samples were collected across the observation period.
What was found
Energy expenditure was 409.7 ± 41.6 kJ (16.6 ± 1.7%) higher in SIT/STAND compared to SIT (p < 0.0001). Postprandial insulin concentrations were 10.9 ± 8.4% lower in SIT/STAND than SIT during the post-breakfast period (p = 0.047), but did not differ in the post-lunch period. Postprandial glucose and triglyceride concentrations showed no statistically significant differences between trials.
Why it matters
Simple, equipment-free physical activity interruptions during prolonged sitting can modestly increase energy expenditure and transiently lower postprandial insulin in individuals with overweight or obesity.
Limits
The sample size was very small (n = 14) and predominantly male (11 men, 3 women). The trial assessed only acute, single-day laboratory responses, so long-term metabolic adaptations and real-world adherence were not evaluated.