title: The effect of changes in cerebral blood flow on cognitive function during exercise.
abstract: No studies have identified the direct effect of changes in cerebral blood flow (CBF) on cognitive function at rest and during exercise. In this study, we manipulated CBF using hypercapnic gas to examine whether an increase in CBF improves cognitive function during prolonged exercise. 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 in which the workload was increased by 0.5 kilopond every minute until a target heart rate of 140 beats/min was achieved. Then, the subjects continued to cycle at a constant rate for 50 min. At four time points during the exercise (0, 10, 20, 50 min), the subjects performed a Stroop test with and without hypercapnic respiratory gas (2.0% CO2), with a random order of the exposures in the two tests. 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 without any loss of performance accuracy. In addition, the hypercapnia-induced increase in MCA Vmean produced neither changes in the reaction time nor error in the Stroop test during exercise. These findings suggest that the changes in CBF are unlikely to affect cognitive function during prolonged exercise. Thus, we conclude that improved cognitive function may be due to cerebral neural activation associated with exercise rather than global cerebral circulatory condition.
authors.affiliation: Graduate School of Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan.
authors.forename: Shigehiko
authors.initials: S
authors.lastname: Ogoh
authors.affiliation: Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: Hayato
authors.initials: H
authors.lastname: Tsukamoto
authors.affiliation: Graduate School of Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Hirasawa
authors.affiliation: Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hasegawa
authors.affiliation: School of Sport Sciences, Waseda University, Saitama, Japan.
authors.forename: Norikazu
authors.initials: N
authors.lastname: Hirose
authors.affiliation: Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hashimoto
keywords: arterial blood pressure; brain; cognition; humans; hypercapnia