Muscle Oxygenation during exercise under hypoxic conditions assessed by spatial-resolved broad-band NIR spectroscopy

摘要

Near-infrared spectroscopy (NIRS) is used for the non-invasive measurement of muscle oxygenation during an incremental cycle test in healthy volunteers. A broad band spatially resolved system is used that allows the reliability of current algorithms to be inspected with the main emphasis on tissue oxygen saturation (SO_2) and oxygenated and deoxygenated haemoglobin concentrations. Physiological conditions were modulated by changing oxygen supply from normal (21 % O_2 in inspired air) to conditions corresponding to 2000 and 4000 m altitude above sea level (15.4 and 11.9 % O_2). Under these hypoxic conditions the decrease in SO_2 with increased exercise power is highly correlated with the oxygen content of the inspired air. There is a clear correlation with physiological parameters (heart rate, pulse oxymetry, blood gas, lactate, spirometric data). Skin oxygenation parameters are compared to those of muscle.