Irregular heartbeat linked to working too many hours

It goes without saying that a job almost always results in a few late-night shifts. However, a new study has found that if you make a habit of being the last one out of the office, you may be putting your health at risk.

In a study of more than 85,000 adults in the U.K., Denmark, Sweden and Finland, researchers found that in a 10-year span, working more than 55 hours per week increased patients' risk for A-fib by 40 percent.

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Officially known as atrial fibrillation, it's considered the most common type of an irregular heartbeat, which could lead to heart failure. The study found those working long 11-hour days increased the rate of incidents.

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Right now, researchers aren't sure why exactly that is. Mika Kivimaki, a researcher at University College London and the lead author of the study, is ruling the results a correlation, not a causation.

And before you quit your job, Kivimaki says a healthy young person with few additional risk factors other than working long hours probably won't develop A-fib.