Being first at the office and the last to leave may help get you that promotion, but new research warns that working long hours may not be so good for your heart.
And the longer you do it, the higher your risk for a stroke, French researchers said.
The findings come from a review of self-reported work habits and heart health among roughly 144 000 French men and women between the ages of 18 and 69.
Those who worked long hours had a 29% greater risk of stroke, and those who worked long hours for at least 10 years had a 45% greater risk of stroke, the analysis found. For the purpose of the study, "long work hours" meant working more than 10 hours a day for at least 50 days out of the year.
"Previous studies in South Korea, the USA and Europe have raised this issue," study author Dr Alexis Descatha said. "But for the first time we had data to show an association with duration, [meaning] 10 years or more."
Descatha is a specialist in emergency medicine at Paris Hospital in Versailles, as well as a professor in occupational health with the French National Institute of Health and Medical Research (Inserm).
He and his colleagues outline their findings in the July issue of the journal Stroke.
Investigators focused on those who had been in the workforce for at least six months. Most were full-time employees.
In addition to completing questionnaires, all participants also underwent medical interviews, during which investigators collected information on past stroke histories; body mass index (a standard measure of overweight/obesity); diabetes and high blood pressure status, and any family history of heart disease.
The team found that about 30% of the French participants said they had worked long hours, while about 10% reported having worked long hours for 10 years or more. After setting aside those who had experienced a stroke prior to embarking on a long work hour routine, roughly 1% of the respondents were characterized as stroke survivors.
In the end, the team found a strong association between working long hours and stroke risk, for men and women alike. The link seemed stronger for people under the age of 50.
Descatha characterised the latter finding as "unexpected", and said more research is needed to understand why younger workers are more affected.
But he suggested it could be that at a younger age the working conditions, irregular schedules and stress that can accompany working long hours might have more of a negative impact on the heart than other factors - such as being overweight and having high blood pressure - that typically affect older men and women.
Greater attention needed
Dr Gregg Fonarow is director of the Ahmanson-UCLA Cardiomyopathy Center and co-director of the UCLA's preventative cardiology programme. He noted that "a variety of potential mechanisms have been considered as helping to explain this excess risk.
"These include long hours spent working leading to less daily physical activity, prolonged sitting, greater exposure to stress, and disruptions in sleep," Fonarow said.
"It has also been suggested that those with long work hours may pay less attention to their cardiovascular health or seek attention for concerning symptoms."
He added that the findings suggest greater attention is needed for modifying cardiovascular risk factors for those who work long hours.
"It is possible to work long hours but still maintain a healthy blood pressure, healthy body weight, healthy cholesterol levels, and get sufficient levels of physical activity to substantially decrease the risk of stroke or heart attack," Fonarow believes.
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