The extra hours also put those workers at a greater risk of developing coronary heart disease. The findings of the study, which analysed 600,000 people, are published in The Lancetmedical journal.

The longer people work the higher their chances of a stroke, says lead author Professor Mika Kivimaki of London’s University College.

The reasons for the greater risk are unclear, but the authors suggest physical inactivity, high alcohol consumption and stress may be factors.

Professor Tony LaMontagne from Melbourne’s Deakin University says the study reinforces other research linking long working hours to a variety of adverse health outcomes and social outcomes.

“In short, the findings of this study, combined with those from others, suggest the need to consider long working hours as a hazard to employee health in Australia,” he said.

Professor Dino Pisaniello from the University of Adelaide said an underlying risk factor for both stroke and coronary heart disease was physical inactivity for extended periods.

“Long working hours is a proxy for other risk factors, which may be more common in workers of low socio-economic status,” he said.

“The Lancetpaper should provide a stimulus for workplaces and regulators to re-examine long working hours, and in particular long periods of physical inactivity for men in lower paid jobs.”

Are you working too hard? 

❏ 41-48 hours a week increases stroke risk by 10 per cent

❏ 49-54 hours increases risk by 27 per cent

❏ 55 hours plus increases risk by 33 per cent