Which of the following factors increases stroke volume?

Stroke volume refers to the amount of blood pumped by the heart with each beat and is influenced by several physiological factors. One significant factor that increases stroke volume is a training-induced decrease in systemic vascular resistance.

When the body is subjected to regular aerobic exercise, there is an adaptation that leads to improved cardiovascular efficiency. A decrease in systemic vascular resistance typically occurs due to vasodilation, which reduces the resistance the heart has to work against when pumping blood. This enhanced blood flow allows the heart to fill more completely during diastole and also eject more blood during systole, which ultimately leads to an increase in stroke volume.

In contrast, the other options do not promote an increase in stroke volume. An increase in systolic blood pressure could mean the heart is working harder, but it does not directly translate to an increase in stroke volume, as it could result from increased afterload without necessarily improving the heart's pumping capacity. Decreased ventricular contractility would reduce the heart's ability to pump blood effectively, leading to a decreased stroke volume. Lastly, a decreased heart size might suggest less muscle mass, which would also contribute to a lower stroke volume, as there is less capacity for blood storage and ejection.

Thus, a training-induced decrease in systemic vascular