After accounting for known heart risk factors such as smoking, doctors found those who worked three to four hours over the ‘normal 8 hours working day’ ran a 60% higher risk.
Experts said the findings highlighted the importance of work-life balance.
Overall, there were 369 cases where people suffered heart disease that caused death, had a heart attack or developed angina and the number of hours worked by those affected appeared to be strongly linked in many cases.
People who spend more time at work have less time to exercise, relax and unwind.
Work/life balance plays a vital role in well-being and people who work excess hours hey may also be more stressed, anxious, or have depression.
A career-minded person will also tend to be a “Type A” personality who is highly driven, aggressive or irritable, they say.
“Employees who work longer hours may also be likely to work whilst ill – that is, be reluctant to be absent from work despite illness,” they added.
Dr John Challenor, from the Society of Occupational Medicine, said: “In many ways it confirms what we as occupational health doctors already know – that work/life balance plays a vital role in well-being.
“Employers and patients need to be aware of all of the risk factors for coronary heart disease and should consider overtime as one factor that may lead to a number of medical conditions.”