A new study has found that working long hours may raise the risk of heart disease.

The research is based on analyzing 1,900 people in a long-term study, which found that 43 percent had a problem related to cardiovascular disease, including heart failure, heart attack and stroke, and the risk for those health ailments rose 1 percent for full-time employees for each additional hour worked per week over 10 years or more, according to a statement from the American College of Occupational and Environmental Medicine (ACOEM)

The risk starts rising past 45 hours. Researchers found that the risk of heart disease was 16 percent higher among those who worked 55 hours per week, and 35 percent higher for those who worked 60 hours per week, according to the report. Those who worked part time did not seem to be affected.

The study provides evidence that there is a connection between long work hours and an increased risk of cardiovascular disease, and therefore prevention efforts focused on work schedule practices can be pursued for the millions of people who work long hours, researchers said.

“In general, we found that the risk of CVD increased as the average weekly working hours increased,” Sadie H. Conway, PhD, of University of Texas Health Sciences Center, Houston, said in a statement, noting that CVD risk is lowest between 40 and 45 hours per week for full-time workers.