Hillary Clinton's bout of pneumonia has shed light on a problem seldom seen by American voters: The long days, little sleep, cross-country travel, bad food and kissing babies add up to a recipe for illness for presidential candidates and aides.
Avoiding viruses and other ailments can be next to impossible for people who spend months in the close confines of campaign planes and buses.
Brooke Buchanan, former press secretary to 2008 Republican presidential candidate Sen. John McCain, remembers leaving the campaign trail in Beaufort, South Carolina, to visit an emergency room. She had a respiratory ailment and two ear infections.