The average cubicle dweller may have his eyes glaze over while staring at a computer monitor, but otherwise, sleep troubles don't pose a huge workplace risk. For police officers, however, it's another story. A new study from researchers at Brigham and Women's Hospital in Boston, published in this week's Journal of the American Medical Association, found that 40 percent of cops have a sleep disorder, affecting their health and job performance, and, in turn, public safety. Here, a brief guide:

What did the study find?
In a survey of 5,000 police officers throughout North America, researchers found that 40 percent had a sleep disorder like insomnia or sleep apnea. Many had gone undiagnosed and untreated. Plus, 46 percent of officers admitted to having fallen asleep while driving, and more than a quarter said they did so at least once a month.

How many Americans have sleep disorders?
Quite a few. Some 40 million people in the U.S. suffer chronic sleep disorders, while another 20 million deal with sleep problems occasionally.

How do sleep disorders affect cops' work?
Sleep-deprived officers were 25 percent more likely to have "uncontrolled anger" when dealing with suspects or citizens, and 43 percent more likely to make serious administrative errors. "We know that sleep deprivation results in impaired performance both cognitively, physically, and emotionally, which can impact decision-making and response time, which are crucial to high stress professions such as law enforcement," says Dr. Nanci Yang, a Stanford professor who was not part of the study. 

Why do so many cops have sleep problems?
Cops work long hours at irregular times. Fourteen- and 16-hour shifts aren't uncommon, and many officers rotate between day and night shifts, causing a condition known as shift work disorder. Plus, getting by on just a few hours sleep can make a cop look tough, macho, and dedicated. Police departments often offer financial rewards for long hours — and the lack of sleep that might go with them — in the form of overtime pay.

How can this problem be addressed?
Health incentives might help. The research also showed that Massachusetts state police officers had lower rates of sleep disorders and obesity than other cops. Why? It might have something to do with the fact that the department gives one hour of paid exercise time for every shift, and ties pay raises to fitness tests.

Sources: ABC News, NPR, TIME