Working longer hours increases risk of stroke

Working 55 hours or more per week is linked to a one-third greater risk of stroke compared to a 35–40 hour work week, according to research published in The Lancet.

Based on a review of 17 studies covering 528,908 men and women followed for an average of 7.2 years, the increased stroke risk remained once smoking, alcohol consumption and level of physical activity were taken into account.

The study found that compared with people who logged a standard week, those working between 41 and 48 hours had a 10 per cent higher risk, while for those working 49 to 54 hours, the risk jumped by 27 per cent. Working 55 hours or more a week increased the risk of having a stroke by 33 per cent, the study showed.

The long work week also increased the risk of developing coronary heart disease by 13 per cent, even after taking into account risk factors including age, sex and socioeconomic status, as per the study.

The underlying causes of stroke and heart disease are complex, involving a mix of genetic and environmental factors. But, the researchers suggest, physical inactivity, high alcohol consumption and repetitive stress all enhance risk.

“The pooling of all available studies on this topic allowed us to investigate the association between working hours and cardiovascular disease risk with greater precision than has previously been possible,” Mika Kivimaki, a professor of epidemiology at University College London, said in a statement.

The study is the largest so far to examine the relationship between working hours and cardiovascular health and is especially noteworthy because it points to stroke as a risk of working long hours. Earlier studies have linked heart attacks to excessive work.

Experts not involved in the study said the findings are important, and pointed to differences across nations in the average length of the work week.