Everyone works overtime to make a little extra cash, but that may change.

A new study shows people working 3 or more hours of overtime a day had a 60% increased risk of heart-related issues from angina to heart-disease related death. Even after taking into account other risk factors like smoking, obesity, and high cholesterol, the statistics still stands.

6,000 British civil servants were studied. For these workers, overtime was associated with type A behavior like aggression, hostility, competitiveness, psychological distress, and sleep problems. The participants were then entered into a larger, ongoing Whitehall II health study of London-based civil service workers.

Workers’ ages ranged from late 30s to early 60s at the time of enrollment. They were followed for an average of 11.2 years for overtime analysis. In the UK, one or two hours over a seven hour workday was considered normal and had little impact on heart health. However, working 10 or more hours a day increased heart risk to 60%.

Lead researcher Marianna Virtanen, PhD, says the risk is “moderate.” The results need to be replicated and then take into account other possible health outcomes like type 2 diabetes.  Yet, more and more research shows an increasing correlation between heart risk and working overtime.

Virtanen says what researchers should do now is determine if a shorter workday will affect the risk of heart disease.