What adverse effects does smoking have on the cardiovascular system?

Smoking has several adverse effects on the cardiovascular system, and one of the most significant is that it promotes atherosclerosis and damages blood vessels. When a person smokes, harmful chemicals in tobacco smoke enter the bloodstream, leading to the formation of plaque in the arteries. This plaque buildup narrows and hardens the arteries, reducing blood flow. The damage to blood vessels also increases the risk of blood clot formation, which can result in heart attacks or strokes.

Additionally, smoking causes chronic inflammation and oxidative stress, which contribute to endothelial dysfunction. The endothelium is the inner lining of blood vessels, and its proper function is crucial for maintaining vascular health. Damage to this lining can further exacerbate the process of atherosclerosis.

In contrast, the other options describe effects that do not occur with smoking. For instance, smoking does not improve blood vessel flexibility or increase oxygen levels in the blood—rather, it has the opposite effects. Furthermore, while smoking may initially lead to a temporary increase in heart rate due to the stimulatory effects of nicotine, it does not lead to a sustained reduction in heart rate. Thus, the option detailing the promotion of atherosclerosis and the damage to blood vessels correctly captures the extensive negative impact of smoking on cardiovascular health.