It hardly seems fair. You have to work long hours because that is your job. Your social life is ruined and you regularly fall asleep into your ready-meal. But, actually, it is even worse: research increasingly shows that working long hours (and British employees work the longest hours in Europe) puts you at greater risk from heart disease and mental health problems. Oh, and it makes you less productive.

The solution

Last month, research using pooled data from eight studies of more than 85,000 workers across Europe showed that working 55 hours or more a week increases your risk of developing atrial fibrillation, a heart condition that causes an irregular and often abnormally fast heart rate and can lead to strokes and heart attacks.

Over the 10 years of the study, people working 55 or more hours had a 40% increase in their risk of developing atrial fibrillation. This increase remained even after the researchers took into account that these workers already had more existing health problems such as obesity and high blood pressure, and that they drank and smoked more than those on shorter hours.

The researchers had published an earlier study using the same database, while studies from the US and Australia in the Lancet two years ago found an increase in the risk of stroke among people working long hours. This latest study identifies atrial fibrillation as a possible trigger.

But medical research is a blunt instrument for identifying the true cost of working too many hours. This study, while big and careful, provides limited evidence for a very small increased risk. Only 1.2% of the workers in the study developed atrial fibrillation, so an increase of 40% still only equates to a 1.7% risk.

Atrial fibrillation has contributory factors, such as high blood pressure, being older, or having diabetes, and there is also a genetic predisposition. The researchers tried to control for changes in some of these co-existing factors over the 10 years of the study, but could not be sure of having done so. Neither did they look at different types of job, such as office-based as opposed to construction work or night shifts. In a long-running study of nurses’ health, night shifts have been linked with a 4% increase in strokes over five years.

You can modify some of the risks of atrial fibrillation – don’t smoke, don’t drink heavily, don’t get obese, and do exercise. But if it is possible, and in any way within your control, don’t work long hours. Presenteeism may please your boss, but it is not good for your heart.