For many long-term care nurses, the idea of working only 40 hours a week, even with scheduled shifts, may seem laughable.

But consistently working between 61 to 70 hours a week increases the risk of coronary heart disease by 42%, a new study finds. Results in the American Journal of Industrial Medicine in September also found that working 71 to 80 hours increases the risk by 63%.

Korean researchers analyzed average working hours for more than 1,000 workers’ compensation cases. They looked at work hours during the week before the onset of illness and average working hours between eight days and three months before onset of cerebro-cardiovascular disease. 

Shift work for healthcare workers also has been linked to negative health, with a 2013 study finding that 32% of healthcare workers report not getting enough sleep. 

Shift work and long work hours also are associated with more obesity and reduced job performance.

Yet another study found women who worked 60 or more hours a week had more than triple the risk of heart disease and asthma, and nearly quadruple the risk of developing arthritis. n