Final answer:
Chronic aerobic exercise leads to increased heart size and efficiency, lower resting heart rate, reduced cardiovascular risk factors, and enhanced insulin sensitivity, with substantial cardiovascular benefits for previously sedentary individuals.
Step-by-step explanation:
The cardiovascular adaptations as a result of chronic aerobic exercise in a previously sedentary individual are numerous and significant. With regular aerobic exercise, the heart muscles strengthen, and the overall efficiency of the cardiovascular system improves. One of the key changes is an increased stroke volume and cardiac output, which means the heart pumps more blood per beat and per minute. Additionally, regular exercise reduces the risk factors for cardiovascular disease, such as hypertension, 'bad' cholesterol (LDL), and excess body weight, while improving levels of 'good' cholesterol (HDL).
Furthermore, an individual's resting heart rate may decrease as the cardiovascular system becomes more efficient at delivering oxygen, and blood vessels may increase in diameter, enhancing blood flow to various parts of the body during exercise. Improved insulin sensitivity is also a benefit of regular aerobic exercise, which contributes to overall metabolic health. Notably, the heart's size and mass can increase in response to exercise, which further supports the heart's ability to pump blood effectively.