What behavior significantly increases the risk of developing heart disease?

Smoking significantly increases the risk of developing heart disease due to its harmful effects on the cardiovascular system. When a person smokes, they expose their body to a variety of toxic substances that can damage the lining of blood vessels, increase blood pressure, and promote the buildup of plaque in the arteries. This process, known as atherosclerosis, narrows the arteries and reduces blood flow, leading to a higher likelihood of heart attacks and strokes.

In addition, smoking leads to increased heart rate and reduced oxygen supply to the heart, which places additional strain on this vital organ. The interplay of these factors not only heightens the risk of heart disease but also contributes to other serious health issues. Thus, among the choices provided, smoking is the behavior that most directly correlates with increased heart disease risk.