Previous studies have suggested that exercise-induced changes in cerebral blood flow (CBF) may be associated with improved cognitive function. However, no studies have identified the direct effect of changes in CBF on cognitive function at rest and during exercise. In the present study, during prolonged exercise, both the speed and the accuracy of cognitive function were assessed using the Stroop color-word test. After the Stroop test at rest, the subjects began exercising on a cycling ergometer. A 5-minute warm-up period was followed by an exercise period in which the workload was increased by 0.5 kilopond every minute until a target heart rate of 140 beats/min was achieved. At the workload reaching target heart rate, the subjects continued to cycle at a constant rate for 50 min. At three time points during the exercise (10, 20, 50 min), the subjects performed a Stroop test. Despite a decrease in the mean blood flow velocity in the middle cerebral artery (MCA Vmean) the reaction time for the Stroop test gradually decreased during the prolonged exercise, while the performance accuracy was unchanged. Prolonged exercise-induced increase in CBF is unlikely to affect cognitive function during prolonged exercise. These findings suggest that cognitive function may be due to cerebral neural activation associated with exercise rather than global cerebral circulatory condition.

DESCENTE SPORTS SCIENCE Vol.36/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE