Pope Francis Health Fact: He Only Has One Lung

You would never know it by looking at him or by listening to him speak to a crowd of thousands, but 76-year-old Pope Francis only has one lung.

Evidently, the Pope had one lung surgically removed when he was a teenager, but has gone on to live an active and vigorous life. He certainly looked and sounded fit, spry, and not short of breath today.

No one is saying why one lung was removed, but back in the 1950s, removal of a lung wasn't that uncommon in cases of severe pneumonia. We just didn't have the antibiotics we have now.

Other reasons for the surgical removal of a lung include things such as an infection caused by a fungus, TB, or a congenital lung problem.

Whatever the reason, living with one lung is not as unusual as you might think. In America, more than 40,000 Americans are living with a single lung after having a lung transplant.

Here's how it the body reacts to having one lung removed: the other grows to compensate -- usually to a point to where the patient has about 80-85 percent of the breathing capacity of a person with two lungs. It just grows and works.

The key is staying healthy is not smoking and keeping your weight within a normal range. Other than that, people with a single lung can usually jog, ski, hike ... and even become a pope.