Entrepreneurs, beware! Those long hours you’re putting in at the office could be killing you. A recent study shows those who spend longer at work are more likely to suffer a stroke.

Researchers found a 33 percent increased risk of stroke among individuals working 55 hours or more per week compared to those working a standard 35- to 40-hour week.

“In the 35- to 40-hour group, there were fewer than five strokes per 1,000 employees per decade,” says Mika Kivimaki, professor of epidemiology at University College London, who conducted the study. Those who worked 55 hours or more experienced six strokes per 1,000 employees per decade.

While previous research linked work stress and stroke, Kivimaki’s study focused on the length of time the participants spent at work. Not surprising to the researchers, stress was found to be more common in individuals who put in longer hours than those working standard hours. But long working hours were not only associated with higher stress levels, but higher risk of suffering a stroke.

Some possible explanations for the correlation are increased releases of fight-or-flight and inflammatory hormones, destabilization of arterial plaque or increased tendency for blood clots. These are all conditions associated with higher stress and physical activity.

“An increasing proportion of jobs are nowadays sedentary and it is possible that part of the health effects of working hours relate simply to a higher number of sedentary hours at work,” says Kivimaki.

Related: How to Maintain a Healthy Lifestyle While Chowing Down at Lunch Meetings

So, what's a busy entrepreneur to do?

Cutting back on your working hours isn’t always possible, especially for entrepreneurs in the startup phase, who often put in 60-plus hours per week. So, for those who can’t help but put in long hours, Kivimaki says there are a number of things you can do to help avoid the negative health consequences of working long hours.

Think of your heart when you eat.

Reduce your daily intake of fat, sodium and alcohol to ensure you keep your blood pressure and blood glucose within normal range.

Get adequate physical activity.

Set a timer to remind yourself to get up every 20 to 30 minutes. Even if you’re typing or talking on the phone, you can still stand. Apps such as BreakTaker can help you ensure you’re spending enough time on your feet. A moving station such as a treadmill desk offer the flexibility of working while moving at 1-2 mph, fast enough to get your heart rate up but not fast enough to distract you from your work.

Avoid excessive stress.

Running a business is stressful, but try deep breathing exercises, take a few minutes every day to meditate or carve out some time in your schedule to do something you enjoy to ensure you don’t allow the stress to become too much for your body to bear.

Related: 7 Physical and Mental Detox Strategies You Should Start Today