Chapter 25, Problem 1CC

If venous P_O2 decreases as exercise intensity increases, what do you know about the P_O2 of muscle cells as exercise intensity increases?

Summary Introduction

To determine: The ${\text{P}}_{0_2}$ of muscle cells when venous ${\text{P}}_{0_2}$ decreases due to increased exercise intensity.

Introduction: Exercise is associated with both increased rate and increased depth of breathing.

Explanation of Solution

During exercise, as the venous blood ${\text{P}}_{0_2}$ decreases, ${\text{P}}_{0_2}$ in the muscle cells also decrease. This is because when muscle cells are working, they take the oxygen out of blood three times as well as when cells are at rest. The ${\text{P}}_{0_2}$ of muscle cells is directly proportional to venous blood ${\text{P}}_{0_2}$.

Conclusion

The decrease in venous ${\text{P}}_{0_2}$ during exercise also decreases ${\text{P}}_{0_2}$ of muscle cells.