2017 Volume 38 Pages 207-215
Cognitive function seems to decline during intense exercise. Concurrently, intense exercise decreases cerebral blood flow and cerebral oxygenation. Given that brain neuronal activity needs adequate oxygen delivery, decrease in cerebral blood flow and cerebral oxygenation may be associated with decline in cognitive function during intense exercise. The purpose of this study was to determine whether decrease in cerebral blood flow and cerebral oxygenation is associated with decline in cognitive function during intense exercise. Fifteen subjects （Age: 23.3 ± 1.8 yr, Height: 1.70 ± 0.06 m, Weight: 64.4 ± 5.8 kg, BMI: 22.5 ± 1.9 m2/kg, peak oxygen uptake （peak V･O2）: 47.3 ± 6.4 ml/min/kg） performed cognitive tasks at rest and during exercise on the cycle ergometer. Exercise intensities corresponded to 50% （moderate） and 80% （intense） of peak V･O2, and exercise duration were 7 min, respectively. The cognitive tasks consisted of Spatial Delayed Response task and GO/NOGO task, which required working memory and executive function. Cognitive function was evaluated by accuracy rate and reaction time of the tasks. Middle cerebral artery mean velocity （MCA Vmean） and cerebral oxygenation were monitored continuously. Cerebral oxygenation was recorded by near infrared spectroscopy and was expressed as changes from baseline. Intense exercise significantly impaired accuracy of the cognitive task as compared with rest and moderate exercise （rest: P < 0.05, moderate P < 0.01）． In contrast, reaction time in the cognitive task was not changed during intense exercise （P = 0.31）． MCA Vmean significantly increased during moderate exercise compared with rest （P < 0.01）． However, it significantly decreased during intense exercise compared with moderate exercise （P < 0.01）． Cerebral oxygenation tended to decrease during intense exercise relative to rest （P = 0.058）． These findings suggested that decreased in cerebral blood flow and cerebral oxygenation during intense exercise may be, least in part, associated with impairment in cognitive function.
