Slow running benefits: Boosts in mood and facilitation of prefrontal cortex function even at very light intensity

Although running upright has been reported to have positive effects on both physical and mental health, the minimum running intensity/speed that would benefit mood and prefrontal cognition is not yet clear. Here, we tested the hypothesis that a brief bout of very slow running, which is classified as a very light intensity exercise, would enhance positive mood and executive function and increase activation in executive-function-related prefrontal subregions. Twenty-four healthy participants completed a 10-minute very slow running session on a treadmill at 35% V̇o_2peak and a resting control session in randomized order. Executive function was measured using the Stroop task and mood state was measured using the Two-Dimensional Mood Scale (TDMS) before and after both sessions. Cortical hemodynamic changes while performing the task were monitored using functional near-infrared spectroscopy (fNIRS). The results show that 10 minutes of very slow running significantly enhanced mood, reduced Stroop interference time (i.e., enhanced executive function), and elicited left lateral PFC activation. Moreover, head acceleration, the magnitude of up-and-down oscillations, was measured during running, and a significant positive correlation with pleasant mood was found. Head acceleration is a remarkable characteristic of running and may be one of the factors related to a pleasant mood induced by very slow running. In conclusion, the current study reveals that a single bout of running, even at very slow speed, elicits a pleasant mood and improved executive function with enhancing activation in prefrontal subregions. This sheds light on the slow running benefits to brain health.