The heart is a muscular organ about the size of a fist located in the upper chest between the lungs. Its job is to pump blood throughout the entire body, supplying it with oxygen and nutrients.
The heart is divided into four chambers: upper left atrium, upper right atrium, lower left ventricle, and lower right ventricle. Each chamber plays a major role in ridding the body of waste and supplying it with new oxygen from the lungs. The heart valves allow the blood to flow in only one direction, through the proper chambers in the correct order. The left ventricle is the strongest chamber, and receives the blood last, pumping it out through the aorta to the rest of the body.
Cardiovascular diseases account for the death of 30% of the population, globally, as of 2008. Coronary artery disease is the most common cardiovascular disease. This is when cholesterol plaques build up inside the arteries, narrowing the blood supply to the heart.
Increased risk factors include smoking, being overweight, not exercising, high cholesterol, high blood pressure, and diabetes. There may be no warning of heart disease until a heart attack is experienced. Healthy lifestyle changes can significantly reduce the risk of heart disease.