The effect of the fraction of inspired oxygen on the NIRS-derived deoxygenated hemoglobin “breakpoint” during ramp-incremental test

During ramp-incremental (RI) exercise to exhaustion, the near-infrared spectroscopy-derived deoxygenated hemoglobin ([HHb]) signal in the vastus lateralis muscle shows a linear increase up to a point at which a plateau-like response is manifested ([HHb] bp ). This study investigated if 1) the [HHb] bp is affected by different fractions of inspired O 2 ([Formula: see text]) [hypoxia (16%; HYPO); normoxia (21%; NORM); hyperoxia (30%; HYPER)]; and...