What is ‘walking pneumonia’ and what does it mean for Hillary Clinton’s health?

Hillary Clinton’s health is in the news after she stepped out of a September 11th memorial service early after feeling overheated. The presidential candidate was diagnosed on Friday with pneumonia and put on antibiotics. According to her physician Dr. Lisa Bardack, Clinton is now "recovering nicely."

But that hasn’t stopped conspiracy theories about Clinton’s failing health, continuing from just a week ago when the focus was on her coughing attacks — despite official records stating that, overall, she seems to doing fine. (The Verge has reached out to the Clinton campaign for an update on her health and whether her travel schedule will change. We will update if we hear back.)

What exactly is Clinton’s so-called "walking pneumonia?"...