Fig. 2
From: Physiologic responses to exercise in survivors of critical illness: an exploratory pilot study
Correlation plots of oxygen utilization measures and peak oxygen consumption during cardiopulmonary exercise testing. Measures of oxygen utilization during exercise and in recovery in cardiopulmonary exercise testing (CPET) are strongly associated with peak oxygen consumption. A Demonstrates the correlation between peak oxygen consumption (VO2Peak) and VO2-work rate slope. VO2-work rate slope quantifies the change in oxygen consumption as work increases during cycle ergometry. Lower values indicate less efficient oxygen consumption and poorer aerobic metabolism (i.e., mitochondrial dysfunction). B The relationship between VO2Peak and VO2 recovery half-time. VO2 recovery half-time quantifies oxygen consumption during recovery after exercise as skeletal muscle creatine is re-phosphorylated by mitochondria via aerobic metabolism. Longer durations of VO2 recovery half-time indicate impaired oxygen utilization and slower re-phosphorylation (i.e., mitochondrial dysfunction). All correlations calculated using Pearson’s correlation coefficient