Your Computer Is Keeping You Awake (and Fat)

If you find yourself having trouble falling asleep at night, reconsider your computer habits. George Brainard, a neurologist at Thomas Jefferson University, says the LED lighting of your computer screen may be slowing your body’s production of melatonin, the hormone that regulates our circadian rhythms. And that’s a problem, because our world is increasingly lit by LED lights.

Old-fashioned light bulbs lean toward the red side of the color spectrum; LED lights lean blue, and blue light is especially good at suppressing melatonin production. Melatonin makes you sleepy, so if your body’s not making enough, your sleep habits will suffer. Study subjects working at blue-toned computer screens for five hours a night produced much less melatonin than those working at fluorescent monitors. And the deficits lasted long after the computers were turned off.

But—and there’s always a but—blue-toned computer users earned higher scores on tests of memory and cognition, suggesting, Brainard says, that blue light provides an “alert stimulus” that could be useful—if you aren’t trying to sleep. He’s hoping to help develop lighting that will alter in wavelength according to the time of day. NASA is interested, since astronauts on the International Space Station would benefit hugely from lights that would keep them alert during working hours and help them sleep at “night.”

And here’s one more reason to worry as we all spend more time indoors, away from natural light. A recent study of mice showed that those exposed to light at night gained 50 percent more weight than mice who stayed in the dark—even when the overall number of calories they consumed was the same.