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

Objective: 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). Methods: 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). Results: 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). Conclusions: 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. Trial registration: ChiCTR1800019120.