What physiological change occurs in response to aerobic exercise training?

Improved stroke volume is a key physiological change that occurs in response to aerobic exercise training. Stroke volume refers to the amount of blood pumped by the heart with each beat. During aerobic training, the heart adapts by becoming more efficient, which typically leads to an increase in stroke volume while at rest and during exercise.

This improvement is primarily a result of several factors associated with enhanced cardiac function, including increased myocardial contractility and improved filling of the heart due to greater venous return. As a person engages in consistent aerobic activities, their heart muscle strengthens, allowing it to pump more blood with each contraction. This increased stroke volume contributes to improved overall cardiovascular efficiency and endurance, allowing individuals to perform physical activities with less effort.

In contrast, the other options represent changes that are either non-typical or detrimental to cardiovascular health. For example, increased resting heart rate or blood pressure at rest can indicate stress on the cardiovascular system rather than improvement. Likewise, decreased lung capacity is not a desirable outcome of aerobic training, as a stronger respiratory system is one of the benefits of regular aerobic exercise. Thus, improved stroke volume is a marker of positive adaptation to aerobic exercise.