With the coming of the season’s chilly winter blasts, health officials are now alerting people that getting to work before daylight arrives and leaving after the sun sets can have seriously negative effects on our mental well-being, the Daily Mail reports.

The warning comes after a recent poll at Mental Health Research UK (MHRUK) found that nearly 10 percent of adults go through winter without ever seeing sunlight during the week. The poll also found that three in 10 adults admitted they worked straight through daylight hours, and nearly half said they were concerned that their workplace had little natural light.

Taken together, these statistics may reveal a burgeoning public health problem, said MHRUK. Several studies show that going without sunshine can cause lethargy and depression over time, which could develop into seasonal affective disorder (a.k.a. SAD) if left unchecked.

SAD isn’t just the “winter blues.” The condition is a type of mood disorder that causes people who are mentally healthy throughout most of the year to experience serious depressive symptoms, such as mood changes, a tendency to overeat and oversleep and difficulty concentrating on, or completing, tasks at work.

“The common unhealthy work culture where lunch breaks are frowned upon is a likely contributor to increasing numbers of SAD sufferers,” said Laura Davidson, PhD, the mental health lawyer and trustee at MHRUK. “Employers and educational establishments need to take on board just how important natural light is to good mental health.”

Davidson added that researchers estimate that nearly 1 million working hours are lost each year to SAD. Scientists also claimed the third Monday of January is the most depressing day of the year.

To help avoid the winter doldrums, try using your lunch hour to revive yourself at work. Research shows doing so might actually make you more productive. Click here for more information.