Does dynamic exercise improve cognitive function in humans?

Abstract

To examine whether acute dynamic exercise could improve cognitive function and the changes in cerebral blood flow of the frontal brain were associated with improved cognitive function, a Stroop color-word test (SCWT) was performed in 12 adults before and after cycling exercise at 20%, 40%, and 60% of maximum voluntary exercise. In SCWT, the subjects were asked to answer a displayed color of a word, which meant "the different color". The total time and the number of errors for 100 SCWT trials were recorded as index of cognitive function. We measured the concentration of oxy-hemoglobin (O₂Hb) in the frontal brain with near-infrared spectroscopy to monitor local cerebral blood flow. 40%- and 60%-exercise for 15 min shortened the total time for SCWT and increased O₂Hb, though 20%-exercise did not alter both of them. The number of error was not altered by any intensity of exercise. The increase in O₂Hb started 5 min after the onset of the exercise and was sustained during and after exercise. When the duration of 40%-exercise was shortened to 5 min, both total time for SCWT and O₂Hb were not altered. These results suggest that acute dynamic exercise at a moderate intensity for a longer period of 15 min, but not 5 min, is able to improve cognitive function and the improved cognitive function may be associated with increased cerebral blood flow of the frontal brain. [J Physiol Sci. 2008;58 Suppl:S145]