Cardiovascular system during exercise of differing intensities and during recovery：練習問題

During a sub-maximal exercise session, an athlete maintains a steady state. How is cardiac output calculated to monitor their physiological response?

Which statement accurately describes the effect of parasympathetic and sympathetic stimulation on the Sinoatrial (SA) node during the recovery phase?

How does the vasomotor centre facilitate the redistribution of blood flow during the transition from rest to maximal exercise?

According to Starling’s Law, why does stroke volume increase during high-intensity exercise?

Which mechanism of venous return is most dependent on the rhythmic contraction and relaxation of the diaphragm and intercostal muscles during high-intensity exercise?

Using the formula \( Q = HR \times SV \), calculate the cardiac output for an athlete at rest with a heart rate of 60 bpm and a stroke volume of 80 ml. Show your final value in litres per minute (L/min).

Explain the specific role of pre-capillary sphincters in the vascular shunt mechanism when an athlete transitions from a resting state to high-intensity anaerobic exercise.

Contrast the intrinsic factors and hormonal factors responsible for the regulation of heart rate during the steady-state period of a marathon compared to the initial anticipatory rise before the race begins.

During the transition from rest to maximal exercise, the body must efficiently manage the venous return of blood to the heart to maintain an elevated stroke volume.

(a) Identify and explain three mechanisms of venous return that become more active during physical activity.
(b) Discuss the relationship between venous return and stroke volume during exercise.
(c) Briefly explain what happens to the mechanisms of venous return during the recovery phase and why a 'cool down' is recommended to prevent blood pooling.

A student records their cardiovascular data during a sub-maximal cycling test. The data shows that at a steady-state intensity, their heart rate is 145 bpm and their stroke volume is 120 ml.

(a) Calculate the student's cardiac output (\(Q\)) in litres per minute (L/min). Show all your working.
(b) Compare and contrast the heart rate response during sub-maximal steady-state exercise versus incremental exercise to exhaustion.
(c) Describe the recovery curve for heart rate immediately following the cessation of high-intensity exercise and explain why heart rate does not return to resting levels immediately.