IStock Photo 3733757 © Max Delson Martins Santos

It’s a nightmare scenario for overworked, overstressed Americans: chest pains, shortness of breath, and a rush of panic signaling that they’re having a heart attack. And it’s a well-grounded fear. The odds that a person aged 20 or older in the United States has had a heart attack are 1 in 27.03, rising to 1 in 10.72 for a person aged 35 or older.

Major cardiovascular diseases killed more than 800,000 people in the United States in 2007, some 33% of total deaths nationwide and more than cancer, accidents, and HIV combined. A person aged 20 or older in the US has a 1 in 2.7 chance of having cardiovascular disease (an umbrella term for heart ailments). And risks rise with age: men aged 50 have a 1 in 1.93 (51.8%) chance of receiving that diagnosis at some point, while the risk for women is 1 in 2.55.

These numbers cover many types of heart trouble. The first warning sign may be angina pectoris, chest pain that occurs when the heart doesn’t get enough blood. Angina can be a sign of coronary artery disease, or damage to arteries that supply blood to the heart, often caused by fatty deposits called plaques that build up inside arteries. If plaques rupture, a blood clot may form at the site and block the artery completely. This triggers a myocardial infarction (heart attack).

In contrast, heart failure happens slowly, over time. The heart becomes too weak or stiff to pump effectively, and fluid backs up into lungs and other organs, usually producing symptoms like fatigue, weakness, and shortage of breath. Heart failure can have many causes: for example, it may be the long-term outcome of a heart attack or may result from high blood pressure, inflammation, congenital heart defects, or alcohol or drug abuse.

Both heart attacks and heart failure can often be treated with medications. Severe cases may require surgery, such as angioplasty, to open a blocked artery; a bypass to restore the flow of blood around a blocked artery; or, in extremes, a heart transplant.

Although some heart disease risk factors can’t be altered, lifestyle choices also weigh in. Eating foods high in saturated fat and cholesterol promotes plaque buildup in arteries, while too much sodium or alcohol raises blood pressure. These connections once spurred the Center for Science in the Public Interest, a Washington, DC-based advocacy group, to label fettuccine Alfredo “ a heart attack on a plate.”

Cigarette smoking, better known for causing lung disease, is also a major contributor to heart problems: it promotes arterial blockages and blood clots, drives up blood pressure, and reduces the ability of blood to carry oxygen. According to two recent reviews, areas of the United States, Canada, and Western European countries that have adopted smoking bans have seen heart attack rates fall by up to one-third within several years.

On the upside, preventive habits like eating well and getting enough exercise can greatly reduce the likelihood of heart attacks or other coronary diseases. And healthy hearts are built for the long haul. A child born today in the United States can expect on average to live to age 78, a span in which his or her heart will beat well over two billion times. As Woody Allen observed in Hannah and Her Sisters, the human heart is “a very, very resilient little muscle.”