Work-related stress and impaired sleep have been linked to a threefold increased risk of cardiovascular disease in employees that have hypertension, according to research from the European Journal of Preventative Cardiology.

Professor Karl-Heinz Ladwig, author of the study, stressed the importance of sleep in recovering from work-related stress. Job stress and poor sleep, he said, often go hand in hand. When combined with hypertension, the effect can be even more toxic. About a third of the working population has high blood pressure.

According to Strom & Associates, constant work-related stress can also cause anxiety and depression, contributing to the risk of cardiovascular disease.

The study included 1,959 workers with high blood pressure aged 25-65. The participants did not have cardiovascular disease or diabetes.

Those who had work-related stress and poor sleep were three times more likely to die from cardiovascular disease compared to those who had no stress and slept well. People who had work stress alone were 1.6-times more likely to die from cardiovascular disease, and those with poor sleep alone had a 1.8-times higher risk.

The study defined work stress as jobs with low control and high demand. Sleep impairment was defined as having difficulty falling asleep and staying asleep.

The study’s findings, according to Professor Ladwig, are a red flag for doctors to ask patients with high blood pressure about their work stress and sleep patterns. He says employers should provide sleep treatment and stress management in the workplace, especially when employees have chronic health conditions like hypertension.

It’s estimated that work-related stress costs the American economy billions of dollars each year.

Some employers are taking measures to tackle the issue of stress, particularly because more employees are suffering from burnout.

In fact, a Gallup survey found about a quarter of U.S. workers feel burned out “very often or always” at work.

Data suggests that burnout should not be ignored by employers. Eventually, it can lead to unexpected absenteeism and does come at a financial cost. According to Gallup’s survey, burned out employees are 63% more likely to take a sick day. A separate study from Eastern Kentucky University in 2016 found that workplace stress costs U.S. employers $300 billion per year.

Burnout also costs $125 billion to $190 billion in healthcare costs each year, according to Harvard Business Review.

If employers take steps to address stress and burnout among workers, it may help lower the risk of cardiovascular disease as per Professor Ladwig’s research.