Question

What causes cardiovascular drift?

A. Increased HR to compensate for reduced blood volume due to sweat production for thermoregularion
B. Decreased HR resulting from an inability to sustain cardiac output due to fatigue
C. Increased stroke volume to compensate for reduced blood volume due to sweat production for thermoregulation
D. Decreased stroke volume resulting from inability to sustain cardiac output due to fatigue

Answer 1

Cardiovascular drift is caused by an increased heart rate to compensate for a reduced blood volume from sweat production, which helps maintain cardiac output during prolonged exercise.

Step-by-step explanation:

Cardiovascular drift refers to the changes in heart rate (HR) and stroke volume (SV) that occur during prolonged exercise. As an individual engages in sustained physical activity, especially in a hot environment, they begin to sweat. Sweating results in a reduction of blood volume, which can potentially decrease cardiac output (CO). To maintain CO and thus ensure that enough oxygenated blood reaches the muscles, the body compensates by gradually increasing the heart rate.

The increased HR is necessary because SV typically starts to decrease due to less blood returning to the heart, a consequence of less time spent in diastole as the HR rises. Therefore, cardiovascular drift is characterized by an increased HR and a decreased SV over time during long-term exercise to maintain CO and manage a stable blood pressure in the face of reduced blood volume.