Which adaptation is NOT associated with regular aerobic exercise?

The adaptation that is not associated with regular aerobic exercise is a higher resting heart rate. Regular aerobic exercise typically leads to various cardiovascular adaptations, one of the most significant being a decrease in resting heart rate. This is a result of improved heart efficiency. As the heart becomes stronger and more effective at pumping blood, it can achieve the same level of circulation with fewer beats per minute.

In contrast, adaptations such as increased heart size, improved stroke volume, and enhanced capillary density are very much associated with regular aerobic training. Increased heart size occurs as the heart muscle strengthens, allowing for greater blood volume to be pumped. Improved stroke volume refers to the amount of blood ejected with each heartbeat, which increases due to the heart’s greater capacity and efficiency. Enhanced capillary density improves the oxygen delivery to muscles, which also results from consistent aerobic workouts. Thus, a higher resting heart rate does not align with the desirable effects of regular aerobic exercise, making it the correct answer.