Sedentary men who work beyond 45 hours a week double their risk of dying from heart failure. However, men who keep fit or exercise and work long hours face no increased risk of dying from cardiac conditions.
The study examined data for 5,000 men - aged between 40 and 59 years from 14 different companies - which included their fitness levels over 30 years, reports the
. The men did cycling exercise tests to assess their fitness and provided details on the average number of hours they worked every week, according to the journal
Around 70 per cent of men worked between 41 and 45 hours a week, while around 20 per cent worked longer hours. Over the course of the study, there were 587 deaths from heart disease caused by the narrowing and hardening of arteries.
Experts found that men who were unfit were at the greatest risk of dying from heart disease, particularly if they worked long hours.
Those who were both unfit and worked more than 45 hours a week were more than twice as likely to die from the disease than men working fewer than 40 hours.
And men who worked 41 to 45 hours a week had a 59 per cent higher risk of dying from heart disease compared to those working under 40 hours.
Physically fit men working longer hours were 45 per cent less likely to die of heart disease and 38 per cent less likely to die of other causes than those who were unfit.
The findings, by a team from the National Research Centre for the Working Environment in Denmark, held true despite factors likely to influence the results, such as work stress and living conditions.