Near-infrared spectroscopy (NIRS) can measure cortical activity during gross motor tasks based on the cerebral hemodynamic response. Although some reports suggest that cycling exercise improves cortical oxygenation, its after-effects are unknown. We examined the after-effects of low- and moderate-intensity cycling exercise on cortical oxygenation. Ten healthy volunteers (mean age 21.3 ± 0.7 years; 4 women) underwent cycle ergometer exercise at 30% or 50% of VO2peak for 20 min, followed by an 8-min post-exercise rest (PER). O2Hb levels of the supplementary motor area (SMA) and sensorimotor cortex (SMC) were recorded using a near-infrared spectroscopy system. Skin blood flow (SBF) and mean arterial pressure (MAP) were continuously measured. The peak values of O2Hb between exercise and PER were compared. The O2Hb, SBF, and MAP increased in the exercise phase. SBF degraded over time, and MAP decreased immediately after exercise. The O2Hb decreased immediately and increased again in the PER. There were no significant differences between exercise and PER in the SMC in the 30% VO2peak experiment or in the SMA and SMC in the 50% VO2peak experiment. The O2Hb in the motor-related area was elevated during both exercise and PER especially in the 50% VO2peak experiment.
Keywords: After-effects; Cortical oxyhemoglobin; Cycling exercise; Moderate-intensity; Motor-related area.