The blue light from the screen of your smartphone or tablet can significantly interrupt your sleep, particularly the melatonin-producing function of your brain, a previous study confirmed.

To help alleviate this problem, Apple on Friday released a new iOS 9.3 feature called Night Shift, in which updated iPhones and iPads can now change the color of the illumination of their screens at night. This is designed to help users cut back on the "harmful" blue wavelengths.

How Blue Light Affects Your Sleep

Gadgets such as iPads and iPhones emit blue light so the screen is visible even during the sunniest time of the day. When the surroundings are dark, however, the brain misinterprets the blue light as sunlight and reduces its melatonin production.

Additionally, the blue light not only slows down the production of melatonin, it also increases the alertness of the user.

"Blue light plays havoc with your sleep by disrupting your circadian rhythms," said neuroscientist Anne-Marie Chang of Pennsylvania State University.

When the circadian rhythm -- the natural body clock -- is changed, it could lead to illnesses such as higher cancer risk, diabetes, or cardiovascular disease.

In the long run, sleep deprivation may affect a person's memory, emotions and performance, as well as increase the risk for obesity.

Mariana Figueiro, the program director of Rensselaer Polytechnic Institute's Lighting Research Center, led a study in 2012 that displayed a relationship between sleep disorders and blue light. Two years later, another study Figueiro supervised had discovered that blue light exposure at night heightens hunger and changes metabolism.

Why The Night Shift Update Is Not A Cure-All

Apple's Night Shift taps into the device's clock and geolocation sensors to find out when to decrease the blue light and shift the spectrum to warmer colors.

The feature makes the screen display look beige or orange, and then goes back to blue in the morning, when it is most beneficial. Night Shift does not work for devices older than the iPhone 5S.

Although the new feature looks promising, sleep experts say it's not a panacea.

"What Apple is doing is very reasonable -- it's based on science. But it isn't just the light," said Dr. Phyllis Zee of Northwestern University.

Meanwhile, Figueiro said Apple's Night Shift is a better option than nothing. Still, she said that it is not just about the color.

"The intensity matters too, so color needs to be shifted and intensity needs to dropped," added Figueiro.

Other experts are also not convinced.

"Just slightly reducing the blue, which is what most apps do, won't accomplish much, so the (sleep) improvements people experience are often mostly due to placebo and their own conscious modification of their behavior in using displays," said DisplayMate Technologies President Raymond Soneira.

What's The Best Solution?

Both Zee and Figueiro agree that a phone app will not simply solve sleep problems.

"If possible, what we strongly encourage is to put your phone away when you prepare for bed," said Zee.

However, Zee acknowledged that putting her smartphone away is hard for her as well, and she is not alone. Many of us are used to checking our gadgets before going to sleep.

Still, Zee said the effect of blue light on circadian rhythm depends greatly on individual lifestyles. She said it would have a greater effect for those who do not get enough bright light exposure for the day, but for farmers who are out all day, the light won't be a problem.

In the end, Figueiro suggests that the solution is to stop using the device two hours before bedtime because that is the time the body begins to produce melatonin.

Photo: Omar Jordan Fawahl | Flickr

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