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Working overtime is great for the wallet, but not for your health, according to a new study. The research found that a person's likelihood of becoming ill grows when they begin working extra hours.

In the largest study of its kind, reported by Politiken newspaper, researchers from the University of Copenhagen and Purdue University found that when Danish production companies experience a surge in business, their employees' workload increases, thereby negatively impacting their health.

In particular, when a production company increases its exports by 10 percent and employees must work extra hours, workers suffer more illness and injuries.

"Our results show that there are real consequences when one is made to work too much," Roland Munch of the University of Copenhagen told Politiken.

This is particularly the case for females. Women are 17.4 percent more likely to have a heart attack when their companies' orders increase, 6.4 percent more likely to suffer workplace injury, and 2.5 percent more likely to develop severe depression.

"You especially see women buying more anti-depressants, and getting diagnosed with heart attacks and strokes to greater extents,"Munch told The Local.

Although men experience a 5 percent increased risk of workplace injuries when their hours are increased, the extra work appears to have no effect on their risk of heart attack.

And while women experienced an increased likelihood of developing depression, men actually became 2 percent less likely to suffer depression when their companies' orders increased.

Munch said the results should encourage companies to think twice before allowing staff to work extra hours during busy times.

"If companies suddenly have their order books full and have to produce more, employers should ask themselves whether they should allow their employees to work more [hours] or whether they should hire more people," he said.

Munch and his colleagues from Purdue University studied health data from five different Danish registries for people employed in the production sector, comparing them with labor records and the amount of exports produced by their companies. In total, the researchers examined more than 150,000 per year, over a period of 12 years.

A similar study published in June also found that working more than 40 hours a week is more detrimental to women, leading to higher chances of cancer and heart disease.