Working long hours — particularly 46 hours per week or more — may increase the long-term risk of cardiovascular disease (CVD) events such as heart attack, reports a study in the March Journal of Occupational and Environmental Medicine, official publication of the American College of Occupational and Environmental Medicine (ACOEM).
“In general, we found that the risk of CVD increased as the average weekly working hours increased,” write Sadie H. Conway, PhD, of University of Texas Health Sciences Center, Houston, and colleagues. They note that among full-time workers, CVD risk appears lowest between 40 and 45 hours per week.
The researchers analyzed the relationship between work hours and CVD using data on more than 1,900 participants from a long-term follow-up study of work and health. All participants had been employed for at least 10 years. During the study, a physician-diagnosed CVD event — angina, coronary heart disease or heart failure, heart attack, high blood pressure, or stroke — occurred in about 43 percent of participants.
Risk of CVD events increased by one percent for each additional hour worked per week over at least 10 years, after adjustment for age, sex, racial/ethnic group, and pay status. The difference was significant only for full-time workers, not part-timers. Among those who worked more than 30 hours per week, risk increased as weekly hours approached 40, but then decreased again between 40 and 45 hours per week.
Beginning at 46 hours, increasing work hours were progressively associated with increased risk of CVD. Compared to people who averaged 45 hours per week for 10 years or longer, overall CVD risk was increased by 16 percent for those who worked 55 hours per week and by 35 percent for those who worked 60 hours per week.