If you exercise regularly, eat a healthy diet, and don’t smoke, you may think you’re doing everything you can to protect yourself against heart disease. But as healthy as these habits are, they may not be enough to stave off a heart attack or stroke.

That’s because heart disease can be a formidable foe. As a leading killer of both men and women in the United States, heart disease accounts for 1 in every 4 deaths — one death every 36 seconds, according to the Centers for Disease Control and Prevention. 

The risk of heart disease increases, in part, as cholesterol and triglyceride levels increase.

Cholesterol is a soft, waxy substance that’s found naturally in the body and helps produce healthy cells, hormones, and more. The body produces all the cholesterol it needs, but as the years go by, people eat foods that increase their levels of low-density lipoprotein (LDL, or “bad”) cholesterol and don’t have enough high-density lipoprotein (HDL, or “good”) cholesterol. 

Over time, this buildup of LDL cholesterol — especially when there’s also an excess of triglycerides, a type of fat in the blood — can clog the arteries with plaques of fatty material (atherosclerosis) and interfere with the blood flow to the heart, brain, and other vital organs. High cholesterol (hypercholesterolemia) and high triglycerides (hypertriglyceridemia) also raise the risk of heart attack, stroke, and other health conditions.

The problem: Not everyone with high cholesterol and triglyceride levels will show signs of it. To be screened for the conditions, you can get a blood test called a complete cholesterol test, generally called a lipid panel or lipid profile, which tells you how much cholesterol and what type is in your bloodstream. Triglycerides can also be measured, but you may need to fast for 9 to 12 hours before the test.

The ideal ranges for healthy cholesterol and triglyceride levels are:

• Total cholesterol: Less than 200 milligrams per deciliter (mg/dL)
• LDL cholesterol: Less than 100 mg/dL
• HDL cholesterol: More than 60 mg/dL (the higher the number the better)
• Triglycerides: Less than 150 mg/dL

If you’re doing all you can to keep your cholesterol and triglyceride levels in a healthy range but your numbers are still high, you may want to talk to your doctor about taking medication, says Stephen Kopecky, MD, a cardiologist at the Mayo Clinic in Rochester, Minnesota. 

Take this quiz to learn how to take control of your cholesterol and triglycerides and protect your heart.