In a commentary to be published in the International Journal of Epidemiology in April, experts say there's a possibility that the more bored you are, the more likely you are to die early.
Annie Britton and Martin Shipley of University College London caution that boredom alone isn't likely to kill you - but it could be a symptom of other risky behavior like drinking, smoking, taking drugs or having a psychological problem.
The researchers analyzed questionnaires completed between 1985 and 1988 by more than 7,500 London civil servants ages 35 to 55. The civil servants were asked if they had felt bored at work during the previous month.
Britton and Shipley then tracked down how many of the participants had died by April 2009. Those who reported they had been very bored were two and a half times more likely to die of a heart problem than those who hadn't reported being bored.
But when the authors made a statistical adjustment for other potential risk factors, like physical activity levels and employment grade, the effect was reduced.
Other experts said while the research was preliminary, the link between boredom and increased heart problems was possible - if not direct.
"Someone who is bored may not be motivated to eat well, exercise, and have a heart-healthy lifestyle. That may make them more likely to have a cardiovascular event," said Dr. Christopher Cannon, an associate professor of medicine at Harvard University and spokesman for the American College of Cardiology.
He also said if people's boredom was ultimately linked to depression, it wouldn't be surprising if they were more susceptible to heart attacks; depression has long been recognized as a risk factor for heart disease. Cannon also said it was possible that when people are bored, dangerous hormones are released in the body that stress the heart.
Britton and Shipley said boredom was probably not in itself that deadly. "The state of boredom is almost certainly a proxy for other risk factors," they wrote. "It is likely that those who were bored were also in poor health."
Others said boredom was potentially as dangerous as stress.
"Boredom is not innocuous," said Sandi Mann, a senior lecturer in occupational psychology at the University of Central Lancashire who studies boredom.
She said boredom is linked to anger suppression, which can raise blood pressure and suppress the body's natural immunity. "People who are bored also tend to eat and drink more, and they're probably not eating carrots and celery sticks," she said.
Still, Mann said it was only people who were chronically bored who should be worried.
"Everybody is bored from time to time," she said.