A study involving 18 volunteers who performed a simple orientation discrimination while on a stationary bicycle, has found that low-intensity exercise boosted activation in the visual cortex, compared with activation levels when at rest or during high-intensity exercise.
The changes suggest that the neurons in the visual cortex were most sensitive to the orientation stimuli during the low-intensity exercise condition relative to the other conditions. It’s suggested that this reflects an evolutionary pressure for the visual system to be more sensitive when the individual is actively exploring the environment (as opposed to, say, running away).
 . Acute Exercise Modulates Feature-selective Responses in Human Cortex. Journal of Cognitive Neuroscience [Internet]. 2016 ;29(4):605 - 618. Available from: http://www.mitpressjournals.org/doi/10.1162/jocn_a_01082