Experts weigh in on the condition

Hillary Clinton made a dramatic exit from a 9/11 memorial event on Sunday, stumbling and needing help getting into her car. At first, people thought she had succumbed to the hot, humid temps in New York City, but it was later revealed that the Democratic presidential nominee was actually suffering from a bout of pneumonia.

Sunday evening, Clinton's personal doctor Lisa R. Bardack, M.D., released a statement saying that Clinton had been diagnosed with pneumonia on Friday. "She was put on antibiotics, and advised to rest and modify her schedule," the physician wrote.

This indeed has all the hallmarks of a classic case of "walking pneumonia" says Chadi Hage, M.D., a pulmonologist and critical care specialist from IU Health. Symptoms of pneumonia include a cough that often produces green or yellow phlegm, chest pain, exhaustion, fever, weakness, and trouble breathing. Patients with "walking pneumonia" experience the same symptoms, but they're generally milder. While full-blown pneumonia is known for sending people to their beds or even the hospital, some patients are still able to function somewhat, hence the "walking" moniker.

"It's a real infection," Hage says, "but people with this condition aren't extremely sick." Unfortunately, though, this can cause even more problems since their mobility may slow down their own recovery.

"Pneumonia is the most common infectious disease-related cause of death worldwide, killing nearly 1 million children under the age of 5 years and more than 20 percent of people over 65 years old," says Ricardo Jorge Paixao Jose, M.D., a respiratory infection specialist at University College in London. At 68 years old, this makes Clinton a prime target for the disease. Doctors recommend getting the pneumococcal vaccine for people aged 65 or older.

Still, pneumonia is an incredibly common illness that could affect anyone. "It's not usually indicative of other conditions," Hage says, reassuring people who worry this is a larger sign of Clinton's possibly failing health. There's no reason to believe this is more than an isolated occurrence.

But other than prescribe the appropriate medication-antibiotics for a bacterial infection or antivirals for a viral infection-there's not much doctors can do other than to encourage rest and hydration, Hage says. It takes an average of five to seven days to clear the infection, although symptoms like a slight cough may linger longer. So, experts expect Clinton to be feeling better within a week.

As for you? Get a flu vaccine every year; influenza is the most common cause of pneumonia. (See also: Do I Really Need to Get the Flu Shot?)