The present study conducted a two-year prospective assessment to define the intensity of daily physical activity which would have a favorable influence on neurocognitve function.
　72 people over the age of 60 participated in this study. They wore an electronic accelerometer throughout their waking hours for three months for assessments which took place during follow-up year. This recorded the number of steps per day and the duration per day as one of ten intensity levels (0.5, 1 to 9) . Executive cognitive function was evaluated with a Task-Switch reaction time (RT) test in the baseline and follow-up year. Percent RT increase (%SwRT) and correct response rates (%CrctRT) in the switch RT trial were considered to study the year related change (or aging decline) of the executive function.
　Within this study, multiple regression analysis detected the amount of light physical activity (< 3METs) as an independent variable which had a positive correlation with the year related difference of %CrctRT. Moreover, the amount of moderate physical activity (>4METs) was detected as the factor which negatively correlated with the year related difference of %SwRT. Additionally, fMRI analysis confirmed that the higher physical activity group showed significantly reduced age-related functional attenuation of prefrontal areas during the Task-Switch RT trials. The present study strongly supported the contribution of moderate physical activity in daily life to the maintenance of neurocognitive function, in more specifically neurocognitive processing speed.

DESCENTE SPORTS SCIENCE Vol.33/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE