Comparison of hourly walking and alternating walking–resistance breaks versus prolonged sitting on 26-h glucose responses in sedentary adults: a randomized crossover trial

To compare 26-h glycemic responses to uninterrupted sitting versus hourly brisk walking breaks and an alternating walking–resistance break strategy in sedentary young adults, with exploratory sensitivity analyses adjusting for energy expenditure (EE). Eighteen sedentary, healthy young adults (11 female; age, mean (SD)=23.7 (2.5) years; BMI, 21.2 (2.0) kg/m 2 ) completed three 26-h laboratory protocols in a randomized crossover design. Each protocol included a 22-h stay in a metabolic chamber and one 9-h intervention: uninterrupted sitting (SIT), 8-min bouts of brisk walking at 60% VO 2 max every 60 min (WALK), or alternating 8-min bouts of simple resistance activities and brisk walking every 60 min (RESWALK). Interstitial glucose was recorded every 5 min by continuous glucose monitoring across the all three 26-h trials; the primary outcome was 26-h glucose incremental area under the curve (iAUC). The primary outcome, 26-h glucose iAUC, showed a significant condition effect (overall p=0.039). Compared with SIT, RESWALK reduced 26-h iAUC by 17.3% (Cohen’s d=−0.61, 95% CI −1.09 to −0.12; p=0.043), while the reduction in WALK was not significant; these effects were attenuated after adjusting for EE (p=0.085). For secondary outcomes, both WALK and RESWALK reduced glucose iAUC during the 9-h intervention window (p≤0.027), with RESWALK being more effective than WALK (p=0.021). However, during the 5-h evening period, iAUC was higher in WALK compared with SIT (p=0.011), while no differences were observed during the 8-h sleep period. Regarding glucose variability, only CONGA_1 was significantly lower in RESWALK versus SIT (p≤0.041). Compared with prolonged sitting, interrupting sedentary behavior with hourly breaks of combined walking and resistance exercises improves 26-h glycemic control in healthy young adults, EE-adjusted sensitivity analyses attenuated the 26-h effect. Walking-only breaks provided daytime benefits but did not significantly improve 26-h glucose exposure. ChiCTR1800019120. • Interrupting sitting every 60 min with brief activity breaks improves 26-h glycemic control. • Alternating walking and resistance break bouts were more effective than walking-only breaks during the daytime period. • This study suggests that break modality may influence glycemic responses, while EE-adjusted results are interpreted as exploratory sensitivity analyses. • Hourly movement breaks may be a practical strategy for sedentary adults.