What is the approximate percentage of oxygen in inhaled air?

Inhaled air contains approximately 21% oxygen, which is the standard composition of the Earth's atmosphere at sea level. Understanding the role of oxygen in the air is crucial for fitness and health, as oxygen is essential for aerobic metabolism in the body, providing the energy necessary for physical activity.

Knowing the composition of inhaled air helps fitness instructors explain the importance of proper breathing techniques during exercise and how oxygen availability can influence performance, endurance, and recovery. The percentages of other gases, such as nitrogen (about 78%) and carbon dioxide (around 0.04%), are also important but do not play the same crucial role in energy production as oxygen does. This is fundamental knowledge for fitness professionals who work with individuals to improve exercise outcomes and overall health.