What is the difference between SpO2 and VO2max and how do they relate to each other in terms of measuring oxygen levels and fitness levels?

SpO2 measures the amount of oxygen in the blood, while VO2max measures the maximum amount of oxygen a person can use during intense exercise. SpO2 is a direct measure of oxygen saturation in the blood, while VO2max is an indirect measure of aerobic fitness. Higher SpO2 levels indicate better oxygenation, while a higher VO2max indicates better cardiovascular fitness. Both are important indicators of overall health and fitness levels.