Exercise Snacks Improve Cognitive Processing Efficiency: Evidence From Behavioral and fNIRS Studies

This study investigated whether a 6-week exercise snacks (ES) intervention enhanced cognitive performance and explored prefrontal neurovascular coupling mechanisms using functional near-infrared spectroscopy (fNIRS). In a randomized controlled trial, 89 high school students were assigned to an ES group (n = 47; three 90-s high-intensity sessions per day, 3 days weekly) or a control group (n = 42). Cognitive performance was assessed via the Stroop task; prefrontal cortex activation and functional connectivity were measured using multi-channel fNIRS. Linear mixed models revealed that ES significantly improved reaction times for both congruent (β = -39.35, p = 0.001) and incongruent tasks (β = -39.87, p = 0.01), with enhanced activation in the right frontopolar area and left dorsolateral prefrontal cortex during congruent and incongruent tasks. ES also strengthened prefrontal functional connectivity. Mediation analyses confirmed that L-DLPFC-R-FPA connectivity mediated the intervention's effect on reaction time (indirect effect β = -74.10, 95% CI: -99.57 to -50.16). These findings suggest that ES enhances neural efficiency, reflected by faster reaction times without compromising accuracy, underpinned by optimizing prefrontal neural synergy. A daily total of 4.5 min of high-intensity micro-exercise serves as a feasible school-based intervention.