Between watching "just one more" episode of Game of Thrones and Insta-creeping 'til the wee hours of the a.m., it's no wonder so many of us have a perma-case of the drowsies. But while some studies indicate that nighttime light exposure is bad for your sleep cycle, the true consequences of constant exposure to your phone's glow are still a mystery.
When you binge watch a show or squeeze in another round of Candy Crush Saga, the light from your tablet or smartphone keeps your body awake by suppressing your melatonin levels—the hormone that signals the body to prep for sleep. And it's this specific hormone shortage that can domino into bigger problems.
"Low melatonin levels are associated with sleeplessness, which can then open the door to health issues like impaired concentration, weakened immune function, depression, diabetes, [and] even heart disease," says Nicole Van Groningen, M.D., internist at NYU Langone Medical Center. "But decreased melatonin levels that result from artificial light may also have adverse effects that go beyond the insomnia it can cause."
That dip in melatonin can eff with your fertility (steady exposure to artificial light at night can warp your internal clock, making it harder to conceive). And, it can increase your risk of breast cancer, since melatonin is a hormone that can help prevent tumor formation, according to research from the University of Georgia. This is especially the case for shift workers, night owls, and women who live in cities, says Van Groningen.
A 2015 study published in the journal Proceedings of the National Academy of Sciences found that too much artificial light increases body fat in mice by as much as 21 per cent—and it's possible the same effect could be seen in humans, says Van Groningen. According to the study, the excess light may put a damper on your kJ-burning skills, hence the body fat increase.
To top it off, artificial light can also do a number on your peepers. Blue light in particular—which computers, televisions, and cell phones are famous for—may cause damage to your eyes, says optometrist Shannon Gleason. "Over time, too much blue light may lead to early onset macular degeneration or cataracts, both of which can cause varying degrees of vision loss," she says.
The bottom line: The research doesn’t say that artificial light causes health issues like weight gain or cancer, just that there's a possible link, says Van Groningen. Keeping your health in check doesn't necessarily mean using a candelabra or communicating via quill pen once the sun goes down—but the more habits you can change to decrease disruptions to your body clock, the better.
Lowering your artificial light dosage could be as easy as choosing to read books instead of ebooks, banning electronics from the bedroom and closing your blinds before bed, says Van Groningen. "You can also try using bulbs that emit lower frequency light—red, yellow, or orange—like those emitted from incandescent lightbulbs," she says. Phew!