In this study, the prefrontal Oxy-Hb decreased or
unchanged until 5 min from the onset of exercise and
gradually increased in proportion to the exercise intensity
until the end of dynamic exercise (Fig. 2), in agreement
with the previous results [17, 18]. Since the Deoxy-Hb was
unchanged throughout exercise except in the initial period,
the signal of Oxy-Hb is considered to reflect regional
cerebral blood flow in the prefrontal cortex [28–30]. It is
known that changes in the Oxy-Hb are positively correlated
with the changes in blood flow velocity of the middle
cerebral artery [17, 18, 31]. MAP increased by
8–16 mmHg during dynamic exercise (Table 1). The small
rises in perfusion pressure may have little influence on the
prefrontal cerebral blood flow, because the increased MAP
during exercise was within the range of cerebral autoregulation
[32]. Instead, it is conceivable that the change in
regional cerebral blood flow follows an increase in neural
activity of the prefrontal cortex, which may in turn cause
improvement of cognitive function.