Computers, TVs and Smartphones May Affect Mental Health

We’ve all heard that spending too much time watching TV, playing video games or in front of the computer can have a negative impact on health, but if you’re quick to blame lack of exercise, you may be missing another culprit: Artificial light at night. Artificial light includes electric light bulbs as well as blue light from electronic screens, and our exposure to it has increased significantly in the last five decades.

Our bodies use light and darkness to trigger the release of a complicated mixture of proteins and hormones that regulate everything from sleep cycles to how we handle stress and recover from injury. When our bodies expect darkness but “see” light, our internal clocks become confused. Imbalanced levels of these chemicals have been linked to health problems including diabetes, heart disease and obesity, and two recent studies have demonstrated a link between light at night and mood disorders, including depression.

One study, published in Molecular Psychiatry and conducted by neuroscience researchers at Ohio State University, found that exposure to light at night caused hamsters’ brains to produce less melatonin and more of a protein that, when released constantly, causes damage that may lead to depression. The study was conducted with adult female hamsters, since human and rodent females are twice as likely as males to develop depression.

The second, published in Applied Ergonomics and conducted by researchers at Rensselaer Polytechnic Institute, showed that exposure to light from electronic screens also affects brain chemistry. Volunteers used tablets, such as iPads, to read, play games and watch movies; two hours of exposure to the screens was enough to reduce melatonin levels by 22 percent. (Melatonin is a hormone that helps to regulate sleep. It is released when it is dark, and suppressed levels of melatonin have been linked to obesity, diabetes and depression.)

According to the National Sleep Foundation, more than 90 percent of Americans are exposed to blue light in the hour before bed. If you unwind in the evening by watching TV, logging onto Facebook or picking up your e-reader—or if your kids spend their evenings texting and IMing friends—there’s good news. Reducing exposure to artificial light can reverse its negative effects. A few ways:

• Make a point of turning off the TV and game consoles a few hours before you need to turn in.
• Watch only the shows you really love, rather than sitting through a half-hour or two of those you really don’t care about.
• Find other activities to relax in the evening: Read a book, do chores you enjoy (or at least don’t mind), take a class, organize game night—invite friends over for Scrabble, backgammon, Bunko or hearts. (Avoid strenuous exercise, which may also be stimulating.)
• Adjust settings on smart phones and tablets so the screen isn’t on the brightest setting.
• Keep bedrooms device-free zones. If your children rely on their phone alarms, invest in old-fashioned alarm clocks.