Changes in the Laterality of Oxygenation in the Prefrontal Cortex and Premotor Area During a 20-Min...

A recent study based on near-infrared spectrometry (NIRS) showed that a single session of moderate-intensity exercise increases the cortical oxyhemoglobin (O₂Hb) level. However, changes in the laterality of O₂Hb throughout such exercises remain unknown. In the present study, we evaluated changes in the laterality of O2Hb in the prefrontal cortex (PFC) and premotor area (PMA) during moderate-intensity cycling for 20 min. Twelve healthy volunteers performed the exercise at 50% of the maximal oxygen consumption after a 3-min rest period. O₂Hb levels in the right (R-) and left (L-) PFC and PMA were measured using multichannel NIRS and averaged every 5 min during the exercise period, and the laterality index (LI) for each 5-min period was calculated. LI for PFC showed significant changes in each period (first, second, third, and fourth periods: -0.40 ± 0.21, -0.03 ± 0.12, 0.14 ± 0.15, and 0.16 ± 0.10, respectively; p < 0.05), whereas that for PMA showed no significant changes (-0.07 ± 0.09, 0.23 ± 0.08, 0.17 ± 0.12, and 0.19 ± 0.09, respectively; p = 0.12). These findings suggest that the laterality of cortical oxygenation in PFC of healthy, young individuals changes during moderate-intensity exercise for 20 min, thus providing an insight into the mechanisms underlying exercise-induced improvements in brain function.