Starting early in your life, your body naturally deposits little streaks of fatty substances, such as cholesterol, on artery walls. As you age, these fatty substances can build up and form plaque. The plaque restricts blood flow. If a plaque ruptures, it can cause a blood clot to form, blocking blood flow. If this occurs in a blood vessel in the heart, it can cause a heart attack.
Certain things, called risk factors, make a person more likely to develop plaque. Risk factors can include age, family history, smoking, high blood pressure, diabetes, high cholesterol, physical inactivity, and being overweight or obese.