Narcissists tend to be unpopular, for sure. And if researchers are to be believed, men with an overly-inflated sense of self could have an increased risk of cardiovascular problems, too.

As a personality trait, narcissism is characterized by a sense of grandiosity, entitlement and low empathy. To measure its effects on the human body, 106 undergraduate students were given a questionnaire that assessed various components of narcissism.

After adding up the entitlement and exploitativeness subscales, researchers came up with what they deemed was an “unhealthy” score, and a “healthy” score was generated by summing up answers about authority, superiority, vanity and self-sufficiency.

The researchers also measured levels of cortisol, a stress-related hormone, in the students’ saliva at two different times under relatively stress-free conditions.

In results published in the journal PLoS ONE, it was found that higher unhealthy narcissism levels were associated with increased cortisol in men, which can heighten the risk of cardiovascular and other health problems. The same effect was not seen in women, and healthy narcissism scores in both genders were not related to cortisol levels at all.

The bottom line? For men, it’s stressful to be so self-absorbed.

“Even though narcissists have grandiose self-perceptions, they also have fragile views of themselves, and often resort to defensive strategies like aggression when their sense of superiority is threatened,” said University of Virginia researcher David Reinhard in a press release issued by the University of Michigan.

In the same release, study researcher Sara Konrath, a University of Michigan psychologist, added, “Given societal definitions of masculinity that overlap with narcissism — for example, the belief that men should be arrogant and dominant — men who endorse stereotypically male sex roles and who are also high in narcissism may feel especially stressed.”