Final answer:
During a run, oxygen is vital for cellular respiration where it helps convert glucose into ATP, providing energy for cells. Oxygen is carried by the blood to the muscles where it allows for the efficient production of ATP necessary for sustained activity. Without sufficient oxygen, cells switch to less efficient energy production methods.
Step-by-step explanation:
While running for three blocks, oxygen is used in your cells for a crucial biological process known as cellular respiration. This process involves turning glucose into adenosine triphosphate (ATP), which is the usable form of energy for cellular functions.
Within two minutes of exercise, the body starts to supply working muscles with oxygen. Initially, this reaction only yields a small amount of ATP, but it is subsequently followed by stages that release significantly more ATP, making the process much more efficient.
Oxygen serves as a reactant in the final stage of cellular respiration, known as oxidative phosphorylation, where it helps to produce ATP. The heart and circulatory system play a critical role in transporting the oxygen from the lungs to tissues and cells that need it.
Blood carries oxygen to the muscles, and when it reaches the cellular level, glucose is broken down more efficiently, resulting in higher ATP production for sustained muscle activity.
Without oxygen, the body resorts to using glycogen through anaerobic metabolism, which provides energy for only a short duration and is much less efficient. Therefore, having a steady supply of oxygen is vital for endurance during physical activities like running.
The significance of oxygen reaches beyond just the production of ATP; it also involves the removal of carbon dioxide, a waste product from cells. The respiratory quotient (RQ) indicates the ratio of carbon dioxide produced to oxygen consumed during metabolism.
Normally, cardiac muscle metabolism is entirely aerobic and relies heavily on a steady oxygen supply carried by hemoglobin and stored in myoglobin within cells.