A related question is whether it's even true that the person is working hard. Working hard shouldn't distract us from whether what was done works, but it does, so there's an incentive to create the impression that one is working hard. In that view, let's look at Hillary Clinton.
Here's Rush Limbaugh on his show yesterday:
[T]here are people out there saying she got pneumonia 'cause she's working so hard. Even General Powell in one of the emails talks about, my God, she's working so hard. She's working so hard she can barely climb the steps to the podium. You know how General Powell defined working hard? Going to three fundraisers in a day and having to fly to two of them. She's just burning at both ends. She's gonna have to slow down. But that's why she's getting pneumonia....Is she working hard? We're barraged with arguments that contain a set component: Hillary works very hard. But has she been working hard these last 4 years? I've been questioning the use of the "hard work" meme to cover for failure and to give credit where it's not due, but quite aside from that is the factual basis of the reputation for working hard. We're invited to believe that Hillary has become unhealthy because she's been working so terribly hard, but it may be that Hillary is unhealthy and she's not working hard because she's unhealthy.
[Her supporters are making the argument that] Hillary Clinton has to work harder than Trump -- he's a man -- she's had to work harder than Trump because the deck's stacked for Trump because Trump is a man. Is that why she's having so many fewer campaign events than Trump? Is that what working harder than Trump means to level the playing field? Is that why when she does show up at a campaign rally, her speeches are almost so short, if you blink you miss them? Is this why she never does press conferences because she's working so hard to level the playing field?
What is she doing? What work is she doing that is so hard she's getting pneumonia for us? She doesn't do campaign appearances very much. When she does, she doesn't speak much at them, and she certainly doesn't do press conferences. In fact, Mrs. Clinton, who's working so hard that she contracted pneumonia for us, practically took the whole month of August off, except for a couple of fundraising dinners....