If you are in the habit of working overtime regularly and also happen to be out-of-shape, then you run a considerably higher risk of dying from heart disease compared to people who are fit and pack their bags at closing time.

A new research conducted in Denmark suggests that lack of fitness was also an equally crucial factor when it came to working late. The study, published in the online edition of the medical journal Heart, found that men who were fit and worked longer hours showed no signs of an enhanced heart risk.

The study reviewed information provided by 5,000 Danish men aged between 40 and 59 who worked at 14 different companies. The research team analyzed their fitness levels at the start of the study and conducted a follow up after 30 years.

During this period, 587 men accounting for about 12 percent of the overall sample size, died as a result of narrowed or hardened arteries, known medically as the ischemic heart disease.

Study author Andreas Holtermann of the National Research Center for Working Environment in Copenhagen, said this was the first study that linked higher rate of heart disease with physically unfit men who worked more than 45 hours a week. "If they relationship is causal, it obviously has major implications for prevention of heart disease," Holtermann was quoted as saying in a press release.

The study reported that compared with men who worked less than 40 hours a week, unfit men who were at work for between 41 to 45 hours were nearly 60 percent more likely to die of heart disease. However, those who were physically fit but worked longer hours showed 38 percent less signs of falling prey to heart disease.

And in case, a person was both unfit and worked more than 45 hours a week, it almost doubled his risk of dying from a heart ailment compared to those who worked less than 40 hours.