Hillary Clinton struggled with overheating and dehydration Sunday as she attended a 9/11 ceremony despite pneumonia that had led her doctor to recommend scaling back her schedule. Far from being evidence of something seriously wrong with the Democratic presidential nominee, this is evidence that Clinton has a grueling schedule and a will to keep going. It’s also, at the most basic level, something many Americans do: We go to work sick.

For many American workers, that’s not a choice, because the United States is one of very few nations that don’t have paid sick leave laws, and many employers don’t offer it:

Four in ten private sector workers – over 40 million people – do not have access to paid sick time. Seven in ten low-wage workers whose earnings are in the bottom 25 percent of earners, lack access to paid sick time. And among those employed in the accommodation and food services, 75 percent must choose between losing pay and showing up to work sick or leaving a sick child at home alone.

That means a lot of people go to work sick rather than leaving the bills unpaid:

A recent survey of food workers showed that nearly 90 percent went to work when they were sick, including more than half who did so “always” or “frequently.” And of those who worked while sick, almost half (45 percent) reported going to work sick because they could not afford to lose pay.

Clinton had a choice—sort of—whether to continue campaigning and attending events.