People with Type D personalities are often anxious, irritable, pessimistic and secretive when it comes to sharing feelings, Denollet said. These traits aren’t known to cause cardiovascular problems, but the review shows that patients who have heart disease and a Type D personality are less likely to benefit from treatments and may be more likely than people of other personality types to have further heart problems after an initial episode.

“A lot of these people keep these emotions built up for a long time, in addition to chronic stress, which can be harmful to the cardiovascular system,” Denollet told MyHealthNewsDaily. In part, that’s because stress can lead to bad habits like smoking and a sedentary lifestyle, he added.