Changes in Cerebral Oxyhaemoglobin Levels During and After a Single 20-Minute Bout of Moderate-Intensity Cycling

Aerobic exercise produces changes in cerebral oxyhaemoglobin (O₂Hb) concentration; however, the effects of exercise on O₂Hb during the post-exercise period remain to be established. The aim of the present study was to evaluate O₂Hb levels during and after a 20-min bout of moderate-intensity cycling exercise. After a 3-min rest period, 12 healthy volunteers (9 women, 3 men) cycled for 20 min at an intensity corresponding to 50% of their VO₂max, after which they were monitored during a 15-min post-exercise rest period. O₂Hb levels in the right (R-PFC) and left prefrontal cortices (L-PFC), right (R-PMA) and left premotor areas (L-PMA), supplementary motor area (SMA), and primary motor cortex (M1) were measured using near-infrared spectroscopy. A one-way repeated-measures analysis of variance (ANOVA) was performed to compare mean pre-exercise O₂Hb levels with O₂Hb levels during the last 5 min of exercise and the last 5 min of the post-exercise rest period. O₂Hb levels increased significantly (p < 0.01) between the pre-exercise rest period and the last 5 min of the exercise session for each region of interest (range: 0.040-0.085 mM·cm). O₂Hb levels did not return to pre-exercise values during the 15-min post-exercise rest period. O₂Hb levels during the last 5 min of the post-exercise rest period were significantly higher than pre-exercise values in the L-PFC, L-PMA, SMA, and M1 (p < 0.01). Our results indicate that cortical oxygenation persists for at least 15 min following a 20-min bout of moderate-intensity cycling, and that aerobic exercise may facilitate neuroplasticity.