What is a significant risk factor for developing heart disease?

Smoking is a significant risk factor for developing heart disease due to its detrimental effects on the cardiovascular system. It can contribute to the buildup of plaque in the arteries, leading to atherosclerosis, which narrows and hardens the arteries and reduces blood flow to the heart. Additionally, smoking can increase blood pressure, reduce oxygen in the blood, and cause inflammation, all of which heighten the risk of heart-related conditions such as coronary heart disease, heart attacks, and strokes.

In contrast, low cholesterol levels, regular exercise, and a high fiber diet are associated with a decreased risk of heart disease. Low cholesterol is generally protective, as high levels of LDL (bad cholesterol) are a known risk factor. Regular exercise helps maintain overall heart health and reduces other risk factors like hypertension and obesity. A high fiber diet is beneficial as it can improve cholesterol levels and promote better cardiovascular health. Thus, while smoking substantially elevates the risk of heart disease, the other options contribute positively to heart health.