5 Things You Didn't Know About Your Heart

Heart Disease Hasn't Always Been the No. 1 Killer

More people die of heart disease in the U.S. than any other cause. It hasn't always been this way.

Relatively few Americans died of heart disease in the 19th century. In 1900, pneumonia, tuberculosis (TB), and diarrhea/enteritis were the top three killers of Americans, according to the CDC. Heart disease came in fourth.

A growing ability to stop infectious diseases -- coupled with radical lifestyle changes brought by modernization (have you plowed a field lately to guarantee that you eat this winter?) -- sent heart disease shooting up the list to No. 1. In 1900, heart disease accounted for about 10 percent of all deaths. Now, heart disease is responsible for 35 to 40 percent of all deaths in the U.S.

Advances in technology and automation during the 20th century meant that fewer of us had to do strenuous physical labor, and those who did still saved themselves a round-trip walk by using cars or buses.

American diets also changed drastically. Whereas most diets consisted of homemade (and hand-made) meals, industrial processes soon introduced a variety of high-fat foods into our lives.

In a 27-year span starting in 1940, the rapid onset and sky-rocketing rates of heart disease led the World Health Organization to label it "the world's most serious epidemic." Heart disease is now our No. 1 killer, but we're guilty as accessories to the crime.