This research will shed new light into the bidirectional relationship between acute aerobic exercise, brain and cognition. This is based on the particular role of executive (cognitive) function during exercise. The rationale of our study is that stimulation of the prefrontal cortex that has been repeatedly associated with executive function, would facilitate or impair self-paced aerobic exercise. This would also affect cognitive performance immediately after exercise. We will use a modified flanker’s task as a form of assessing executive function (see below for further details). The flanker’s task implies two different stimuli, one congruent and one incongruent. Relative to “congruent” stimuli, these “incongruent” stimuli are usually accompanied by increased response times (RTs) and decreased accuracy. To stimulate the prefrontal cortex, we use transcranial direct-current stimulation (tDCS). tDCS is able to induce cortical changes by hyperpolarizing (anodal) or depolarizing (cathodal) neuron’s resting membrane potential. Therefore, the hypotheses of this research are: 1) Anodal stimulation (relative to sham and cathodal stimulation) will improve self-paced aerobic exercise and, consequently it will also improve subsequent cognitive performance. 2) Cathodal stimulation (relative to sham and anodal stimulation) will impair self-paced aerobic exercise and subsequent cognitive performance.