Aerobic fitness influences cerebral oxygenation response to maximal exercise in healthy subjects

Kahina Oussaidene, Fabrice Prieur, Semah Tagougui, Abdelbasset Abaidia, Regis Matran, Patrick Mucci

The study examined whether the aerobic fitness level modifies the cerebral oxygenation response to incremental ramp exercise, and more specifically the decline in cerebral oxygenation from heavy exercise up to maximal intensities. 11 untrained ( [Formula: see text] 47.3±4.0mLmin(-1)kg(-1)) and 13 endurance-trained ( [Formula: see text] 61.2±8.0mLmin(-1)kg(-1)) healthy men performed a maximal ramp cycle exercise. Left prefrontal cortex oxygenation (ΔHbO2) was monitored by near-infrared spectroscopy. A cerebral oxygenation threshold decline (ThCOx) during exercise was determined. ThCox occurred in all subjects but for higher [Formula: see text] (mLmin(-1)kg(-1)) in endurance-trained than in untrained subjects (P<0.01). At submaximal exercise intensity corresponding to ThCOx, ΔHbO2 was higher in endurance-trained than in untrained subjects (P<0.05). [Formula: see text] at ThCox was related to [Formula: see text] at respiratory compensation point (n=24, r=0.93, P<0.001) and to [Formula: see text] (n=24, r=0.92, P<0.001). These findings indicate that above the respiratory compensation point the prefrontal O2 demand exceeds the supply in untrained and in endurance-trained subjects. In addition, the occurrence of ThCOx was delayed to higher absolute exercise intensities in endurance-trained in relation with their higher [Formula: see text] than untrained men. These results demonstrated that aerobic fitness influences cerebral oxygenation during exercise.