Exercise Physiology Practice Questions

Q: During moderately intense isotonic exercise, all of the following increase except:

Total Peripheral resistance. ***Total Peripheral resistance*** - During isotonic exercise, **vasodilation** in working muscles leads to a decrease in **total peripheral resistance** to facilitate increased blood flow and oxygen delivery. - While some vascular beds constrict, the overwhelming effect of vasodilation in active muscles causes a net decrease in overall resistance. *Mean arterial pressure* - **Mean arterial pressure** typically increases during isotonic exercise due to a significant rise in **cardiac output** that outweighs the decrease in total peripheral resistance. - This increase helps maintain adequate perfusion pressure to active muscles and other vital organs. *Heart rate* - **Heart rate** increases proportionally with exercise intensity during isotonic exercise to meet the increased metabolic demands of the working muscles. - This is a primary mechanism to boost **cardiac output** and oxygen transport. *Respiratory rate* - **Respiratory rate** increases during isotonic exercise to enhance **gas exchange**, removing CO2 and taking in more O2 to support the heightened metabolic activity. - This response is driven by the body's need to maintain **acid-base balance** and provide sufficient oxygen to tissues.

Q: During a maximal exercise test, which of the following best describes the likely changes in his muscle oxygen extraction and arteriovenous oxygen difference (a-vO2 diff)?

Increased muscle oxygen extraction and increased a-vO2 diff. ***Increased muscle oxygen extraction and increased a-vO2 diff*** - During **maximal exercise**, skeletal muscles have a significantly **higher metabolic demand** for oxygen to produce ATP. - This increased demand leads to greater **oxygen extraction** from the blood by the muscles, resulting in a larger difference between the arterial and venous oxygen content (**a-vO2 diff**). *Decreased muscle oxygen extraction and decreased a-vO2 diff* - This scenario would imply a **reduced oxygen utilization** by the muscles and a smaller difference in oxygen content, which is contrary to the body's physiological response during intense exercise. - Such a decrease would lead to rapid **fatigue** and an inability to sustain high-intensity activity due to insufficient energy production. *Increased muscle oxygen extraction and decreased a-vO2 diff* - An increase in muscle oxygen extraction is correct, but a **decreased a-vO2 diff** is contradictory. If more oxygen is extracted, the venous oxygen content would be lower, thereby increasing the a-vO2 diff. - A decreased a-vO2 diff alongside increased extraction would suggest an unphysiologic process or an error in understanding the relationship between these two variables. *Decreased muscle oxygen extraction and increased a-vO2 diff* - This option presents a contradiction: a **decreased muscle oxygen extraction** would logically lead to a *smaller* a-vO2 diff, as less oxygen is being removed from the blood. - An increased a-vO2 diff would only occur with *increased* oxygen extraction by the tissues.

Question 1

During moderately intense isotonic exercise, all of the following increase except:

Accepted Answer

Total Peripheral resistance

Answer

Respiratory rate

Answer

Heart rate

Answer

Mean arterial pressure

Question 2

During a maximal exercise test, which of the following best describes the likely changes in his muscle oxygen extraction and arteriovenous oxygen difference (a-vO2 diff)?

Accepted Answer

Increased muscle oxygen extraction and increased a-vO2 diff

Answer

Decreased muscle oxygen extraction and decreased a-vO2 diff

Answer

Increased muscle oxygen extraction and decreased a-vO2 diff

Answer

Decreased muscle oxygen extraction and increased a-vO2 diff

Exercise Physiology — MCQs

Exercise Physiology — MCQs

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