NETA Personal Trainer Practice Exam

What does oxygen extraction (a-vO2diff) indicate?

1. Amount of oxygen inhaled

2. Amount of oxygen transported by blood

3. Amount of oxygen removed as blood circulates

4. Amount of oxygen stored in cells

The correct answer is: Amount of oxygen removed as blood circulates

Oxygen extraction, represented as a-vO2diff, indicates the amount of oxygen that is removed from the blood as it circulates through the body's tissues. This measurement reflects how effectively tissues are utilizing the oxygen transported to them, providing insights into the efficiency of the cardiovascular system and the metabolic demands of the tissues. When oxygen-rich blood flows from the heart to various tissues, some of that oxygen is extracted and used by the cells for metabolic processes. The a-vO2diff value is calculated by subtracting the amount of oxygen in the venous blood (after the oxygen has been used) from the amount of oxygen in the arterial blood (before it reaches the tissues). A higher a-vO2diff indicates a greater extraction of oxygen by the tissues, suggesting that they are efficiently using the available oxygen to meet their metabolic needs. Conversely, a lower value may suggest that the tissues are not extracting as much oxygen, which could imply a reduced demand for oxygen due to rest or a potential issue with cardiovascular or respiratory function. In contrast, the other options refer to concepts that do not directly correlate with oxygen extraction. The amount of oxygen inhaled pertains to pulmonary function, while the amount of oxygen transported by blood relates to the blood's