The VO2 max has been found to be less than 20 ml/kg/min in _____.

• A. Endurance athletes
• B. Normal healthy adults
• C. Children
• D. Patients with severe pulmonary disease

Answer: (D)

VO2 max is the maximum rate at which the body can take in, transport, and use oxygen during intense exercise. It reflects how well the lungs can ventilate, how effectively the heart and circulation can deliver oxygen to the muscles, and how efficiently the muscles can use that oxygen. In endurance athletes, this ceiling is pushed higher by training adaptations that boost cardiac output and muscular oxidative capacity. In healthy adults, VO2 max sits in a moderate range, reflecting normal cardiopulmonary function. Children vary, but they generally do not typically sit at such low values as an indicator of normal function.

When someone has severe pulmonary disease, the lungs’ ability to ventilate air, diffuse oxygen into the blood, and match ventilation to perfusion is greatly impaired. This dramatically limits the amount of oxygen that can reach the bloodstream and be used by the muscles, so VO2 max falls well below 20 ml/kg/min in many cases. This is why the statement points to patients with severe pulmonary disease as the group with VO2 max under 20.