Mommy blogger Titania Jordan tosses and turns for hours each night, and she thinks she knows why.

"From about 7 p.m. until midnight, I am in front of a screen. I'm on the computer; I'm on my mobile device," she explains.

Jordan is on to something.  Researchers, including Harvard University's Dr. Steven Lockley, have long known that light suppresses melatonin, a hormone that helps regulate sleep.   But now-a-days, we're flooded with light long after the sun sets  We're texting, emailing or catching up on TV.

"It's a very unnatural thing for us to do, and so when we expose ourselves to light at night, we tell the brain that it's daytime." says Lockley, author of Sleep: A Very Short Introduction.

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When we expose ourselves to light at night, it makes it harder to catch some Z's and shift our internal body clock, or circadian rhythm.  the American Academy of Sleep Medicine says it's important to raise a red flag about blue wavelengths, the kind emitted by energy efficient light bulbs and electronic gadgets.

"We know that blue light has the greatest propensity to alter circadian rhythms, and yet now-a-days it seems that blue is the color du jour," says Dr. Nathaniel Watson with the American Academy of Sleep Medicine.

In fact, a National Sleep Foundation poll revealed that 95 percent of Americans use electronics a few nights a week, within an hour before bed.   Lockley says even dim light can be problematic.

"We've done a number of studies to show that light levels that you would be normally exposed to in the home in the evening, for example from a bedside lamp, are very easily capable of shifting the body clock," he says.

And research shows our health may be at risk.  Studies have linked blue light and poor sleep to depression, diabetes, obesity and cardiovascular problems.

"Shift workers have been found to have about a 50 percent to 60 percent increased risk of cancer, particularly breast cancer in women and prostate cancer in men," says Lockley.

So what's a gadget addict to do?  Have a regular bed time routine, sleep in a cool, dark room and most importantly, power down early - ideally two to three hours before bed.

"If you must have screen time before going to bed then limiting the amount of light that's emitted from the screen would be helpful, so you can turn down the brightness," says Watson.

We asked Jordan to cut back on screen time and she says the results were eye opening.

"It was fabulous. I didn't go to sleep right away, but I found myself feeling much more relaxed," she says.

Exposing yourself to lots of bright light during the day can also help.  Lockley says it keeps you alert and helps your body clock reset each night.