Limitations of skeletal muscle oxygen delivery and utilization during moderate-intensity exercise in moderately impaired patients with chronic heart failure

This study provides novel evidence for heterogeneity regarding O2 delivery or utilization impairments to moderate-intensity exercise in patients with chronic heart failure by near-infrared spectroscopy measurements of skeletal muscle oxygenation. Slowed deoxygenation during onset was related to an O2 utilization impairment, whereas a deoxygenation overshoot indicated an O2 delivery to utilization mismatch.