Consider yourself lucky if you're in a job that you love, but be aware that there's a potential downside – other people might take advantage of your passion for your work.

New research shows that managers often set extra hours without pay, or give out demeaning tasks to employees, to those who are particularly passionate about what they do. In other words, your love for your job could be used against you.

Looking at eight previous studies involving more than 2,400 participants in total, the researchers found something they termed "legitimate exploitation" – the sense that it's more acceptable to take advantage of people who are really into their work.

"It's great to love your work," says one of the researchers, Aaron Kay from Duke University in North Carolina. "But there can be costs when we think of the workplace as somewhere workers get to pursue their passions."

This legitimate exploitation might involve getting employees to work over weekends or through holidays, for example. It could also mean asking people to do tasks that aren't really part of their job description.

There was significant variation in the eight previous studies the team of researchers looked at, in terms of the kinds of jobs involved and how the participants were selected. This tendency to take advantage was a common thread through them all, though.

One study found that it was perceived to be more acceptable to exploit artists who were passionate about their work than those that weren't – even down to cleaning the office bathroom. Another revealed that exploitation is more acceptable to people in jobs associated with a passionate connection, like an artist or a social worker.

The research found a reverse effect too: that staff who were exploited in their job were then seen as being more passionate about it. This could "legitimise instances of mistreatment" according to one of the team, Troy Campbell from the University of Oregon.

A couple of psychological factors were uncovered to explain the analysis: one, that people see work as bringing its own reward for people who are passionate about it, and two, that the employees in question would have volunteered anyway.

The researchers describe that as "compensatory justification", something we do when trying to explain away injustice. Another example would be rationalising wealth inequality by arguing that riches bring their own problems, and make life less straightforward.

The team behind the new study admits that trying to guard against this legitimate exploitation problem is tricky – but the researchers do also say that we can start by checking our own behaviours towards colleagues and friends.

And if you do love your job – that's something to be cherished rather than anything to get worried about. Most of us spend a lot of time at work, and spending those hours in an engaged and positive mood is always going to be beneficial.

"Our research is not anti-passion," says one of the researchers, Jay Kim from Duke University. "There is excellent evidence that passionate workers benefit in many ways."

"It's simply a warning that we should not let the current cultural emphasis on finding passion in our work be co-opted by the human tendency to legitimise or ignore exploitation."

The research has been published in the Journal of Personality and Social Psychology.