Which of the following is a risk factor for heart disease?

• A. Smoking
• B. Regular exercise
• C. Adequate sleep
• D. Low-fat diet

Answer: (A)

Smoking raises the risk of heart disease through several interrelated effects on the cardiovascular system. The chemicals in tobacco damage the inner lining of blood vessels, promoting atherosclerosis—the buildup of plaques in the arteries. This not only narrows arteries but also makes plaques more prone to rupture, which can trigger heart attacks or strokes. Smoking also increases oxidative stress and inflammation, raises blood pressure and heart rate, and makes the blood more prone to clotting. Carbon monoxide from smoke reduces the blood’s oxygen-carrying capacity, further stressing the heart. In contrast, regular exercise, adequate sleep, and a low-fat diet are protective factors that improve blood pressure, lipid profiles, endothelial function, and overall vascular health, reducing heart disease risk.