Interrupting sitting with moderate-intensity physical activity breaks improves inhibitory control in adults with overweight and obesity: Findings from the SITLess pilot randomized crossover trial

Introduction: Adults with overweight and obesity (OW/OB) show deficits in inhibitory control, which may be amplified by prolonged sitting. This study tested the acute effects of interrupting 3-h prolonged sitting every 30 min with 3.5-min moderate-intensity physical activity bouts (MPA + SIT) on inhibitory control relative to a sedentary social interaction condition (SOC + SIT) in young and middle-aged adults with OW/OB. Method: Data from 19 adults (63% females; 29.9 ± 7.5 years; BMI = 30.0 ± 3.64 kg∗m⁻²) were analysed from the SITLess pilot randomized crossover trial. Inhibitory control was expressed as response accuracy and reaction time (RT) on incongruent trials of a flanker task. Choice RT was expressed as accuracy and RT on congruent trials. Attentional resource allocation and the speed of stimulus evaluation were measured using the amplitude and latency of the P3b component of event-related brain potentials, respectively. Intervention effects were tested using Generalized Linear Mixed Models with Time (pre, post) by Condition (MPA + SIT vs. SOC + SIT) interactions and simple effects within each time point. Results: Participants were faster on incongruent trials after MPA + SIT than SOC + SIT (F(18.0, 54) = 5.59, p = 0.02; △M = 16.7 ms, 95% CI: 1.64, 31.7). A similar trend (F(18.0, 54) = 4.03, p = 0.05) emerged for congruent trials (△M = 17.3 ms, 95% CI: 5.66, 29.0). P3b amplitude and latency did not differ between conditions or time. Conclusion: Interrupting sitting with short MPA bouts is a viable strategy to prevent a decline in cognitive performance following a continuous bout of sitting in adults with OW/OB. A definitive trial should test its efficacy in enhancing cognitive and brain health in obesity.