America is a success-minded nation. Perseverance is practically a national resource. Posters of mountain climbers that read “Winners Never Quit, and Quitters Never Win” might as well be state-mandated signage in grade-school classrooms. But new research suggests that success — or more specifically, the persistence required to achieve hard-to-reach goals — may not be worth it.

In a paper published in the September issue of the journal Psychological Science, Gregory Miller of the University of British Columbia and Carsten Wrosch of Concordia University found that teenage girls who are unable to disengage themselves from trying to attain hard-to-reach goals exhibited increased levels of the inflammatory molecule C-reactive protein (C.R.P.), which in adults is linked with diabetes, heart disease and early aging. “There’s this traditional idea in Western culture and science literature that being persistent is good, that if you work hard, you can achieve anything,” says Miller, who has published several papers with Wrosch on the psychology of quitting. “Our take is that persistence is good, but there are times where the most adaptive thing is to say, ‘This goal is not going to work out.’ ”

At the outset of their experiment, Miller and Wrosch asked each teenage subject what would count for her as adversity and what would count as success. Then the researchers tracked how the young women dealt with their own setbacks and adversity over the course of a year. What mattered, it turned out, was not whether the subjects achieved success but what they had to endure to get there. “We found that the girls who were best able to disengage when a goal became difficult or unattainable are those who have constant levels of C.R.P.,” Miller says. Teenagers who persisted — even if they eventually attained their goals — had significantly elevated levels. “Success in some cases is going to be costly,” he adds.

None of this is to say that persistence is a bad thing — just that too much of it can be unhealthy. “The million-dollar question,” Miller says, “is where that exact tipping point is.”