What is the approximate percentage of oxygen utilized by muscles during rest?

During rest, muscles typically utilize about 25% of the available oxygen. This percentage reflects the body's energy needs and how it efficiently uses oxygen for aerobic metabolism to produce ATP, which is essential for muscle function. At rest, the body is primarily in a state of aerobic metabolism, relying on oxygen to sustainably generate energy.

The remaining oxygen is usually available for other bodily functions and tissues, such as the brain and organs, which also require a significant amount of oxygen even when the body is not actively engaging in strenuous physical activity. Therefore, the utilization of oxygen at rest is a crucial aspect of understanding how the body manages energy consumption and oxygen delivery, as it highlights the balance between efficiency and demand in maintaining physiological functions.