During a graded exercise test, what is directly measured to determine VO2 max?

• A. Oxygen consumption.
• B. Blood pressure.
• C. Blood glucose.
• D. Body fat percentage.

Answer: (D)

VO2 max is the maximum rate at which the body can take up and utilise oxygen during intense exercise. In a graded exercise test, this is determined by directly measuring oxygen consumption with a metabolic cart that analyzes the oxygen and carbon dioxide in the breath on a breath-by-breath basis as workload increases until exhaustion. The measured oxygen uptake is reported as VO2, typically in mL of O2 per kg per minute. Blood pressure shows how the heart responds, but it doesn’t quantify oxygen being used by the muscles. Blood glucose and body fat percentage reflect metabolic status or composition, not the actual peak oxygen uptake. So the directly measured variable for VO2 max is oxygen consumption.