Slideshow: Pope Francis: His life before the papacy

Marcos Brindicci / Reuters

Cardinal Jorge Bergoglio of Argentina was elected to lead the Catholic Church following the resignation of Pope Benedict XVI. 

Launch slideshow

Vatican officials now say that the new Pope Francis lost just part of a lung to disease as a young man, and that the injury has never affected his work. 

Cardinal Jorge Mario Bergoglio of Buenos Aires had a pulmonary illness some 40 years ago during which part of one lung was removed, according to Fr. Frederico Lombardi, director of the Holy See Press Office. 

"This has never been an obstacle either in his rhythm or for his work, his life, or his pastoral care, as demonstrated by leading a diocese that requires such dedication as that of Buenos Aires," Lombardi said in a press release issued by the Vatican on Thursday. 

Early reports had suggested that Bergoglio had only one lung. 

Still, doctors said that any significant lung loss likely hadn't limited the 76-year-old pontiff's energy or actions in the past -- and shouldn't stop him in the future. 

Pope Francis appears to be fit and lean and should have lung capacity that is nearly normal, said Dr. Zab Mosenifar, a lung expert at Cedars Sinai Medical Center in Los Angeles. 

"It just didn't faze me," Mosenifar said. 

The new pope likely lost part of his lung decades ago, at a time when severe fungal infections or pneumonia were treated with surgery because antibiotics weren't widely available. But his existing lung likely grew and expanded to near-normal capacity within a year or two, said Mosenifar, who is co-medical director of the Women's Guild Lung Institute. 

Human lungs have excess capacity, which is why doctors typically use only one lung in transplants. There are likely 30,000 to 40,000 transplant patients in the U.S. living with one lung, and thousands more who lost an entire lung or part of a lung to disease or trauma, Mosenifar said. 

Many single-lung patients go on to have not only normal lives, but active ones, said Dr. Edward Salerno, a pulmonologist with Hartford Hospital in Hartford, Conn. 

"They can exercise and not feel any dysfunction," he said.  

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