Enhanced muscle activity during interrupted sitting improves glycemic control in overweight and obese men.
Level 2 - randomized trial
Randomized crossover trial
PubMed 38629807 · doi:10.1111/sms.14628
What was done
Eighteen overweight and obese young men (mean age 21.0 ± 1.2 years, BMI 28.8 ± 2.2 kg/m²) completed a randomized four-arm crossover trial evaluating 8.5-hour sitting protocols: uninterrupted sitting (SIT), sitting interrupted by a single 30-minute walk at 4 km/h (ONE), sitting interrupted by 3-minute walks at 4 km/h every 45 minutes for 10 bouts (WALK), and sitting interrupted by 3-minute squat breaks every 45 minutes for 10 bouts (SQUAT). The active conditions were matched for duration and energy expenditure. Continuous glucose monitoring measured net incremental area under the curve (net iAUC) for glucose, and electromyography (EMG) of the quadriceps, hamstrings, and gluteal muscles measured muscle activity amplitude and duration.
What was found
Compared with uninterrupted sitting (glucose net iAUC: 10.2 mmol/L/h [95% CI 6.3 to 11.7]), all exercise conditions reduced glucose net iAUC (all p < 0.05): ONE reached 9.2 mmol/L/h [95% CI 8.0 to 10.4], WALK reached 7.9 mmol/L/h [95% CI 6.4 to 9.3], and SQUAT reached 7.9 mmol/L/h [95% CI 6.4 to 9.3]. Both WALK and SQUAT achieved lower glucose net iAUC than ONE (p < 0.05). Increased average EMG amplitude in the quadriceps (-0.383 mmol/L/h [-0.581 to -0.184], p < 0.001) and gluteal muscles (-0.322 mmol/L/h [-0.593 to -0.051], p = 0.022) was significantly associated with reduced glycemic response.
Why it matters
Breaking up prolonged sitting with frequent short activity bouts improves postprandial glucose control more than a single continuous bout of matched energy expenditure, linked to higher muscle activation intensity during transitions.
Limits
The sample was small (18 participants) and restricted to young overweight/obese males, limiting generalizability to females, older adults, or clinical populations. Only acute 8.5-hour single-day responses were assessed under laboratory conditions.
Cited by
- context Performing 10 bodyweight squats every 45 minutes over an 8-hour workday improved glucose clearance more effectively than a continuous 30-minute walk.