Now here's a surprise; Mrs. Cinton has a body double. I would never guess - being sarcastic - especially as a lot of celebrities employ doubles for many reasons.
That said, there are serious concerns over her health. The reason for not standing down for the good of the Democratic Party has changed from trying to erase the stigma of her husband's shame, to pure bloody-mindedness at being in the White House. Mrs. Clinton may only be in office a few months, but she'll be there if she can.