But in terms of eye health, there’s no reason to spend your time and money looking for blue-light-filtering glasses or gadgets, says Dr. There are plenty of reasons other than sleeplessness to not spend all your time staring at screens, from possible mental health consequences to their correlation with a sedentary lifestyle. Should I try to limit blue light exposure? “You can’t have your blue light filter on, and then have your phone or your tablet at maximal brightness” and expect to drift right off with no problem. “You can’t just worry about spectrum alone,” she says. Goldstein adds that the spectrum of light isn’t the only thing that matters-so do brightness, and duration of exposure. “In over 20 years of practicing sleep medicine, I have never had a patient come to me and say, ‘Hey, doc, can you help me fall asleep 10 minutes faster?'” Wyatt says. While it did show that bedtime exposure to blue light through an iPad can suppress melatonin, Wyatt notes that people who read on their devices for hours took only 10 minutes longer to fall asleep than paper book readers. That is, most experimental conditions don’t correspond to the average person’s day, and even then they often result in only tiny changes in sleep. But Wyatt says most human research done in this field hasn’t been representative of the way the average person is exposed to blue light. There is a valid scientific basis to the idea that blue light interrupts sleep, since research consistently shows that light of any kind suppresses melatonin and blue light may do so to an especially extreme degree. In Wyatt’s view, recommendations around limiting blue light have far outpaced science around its effects. “We put the cart so far ahead of the horse” with blue light, agrees James Wyatt, who directs sleep disorders and sleep-wake research at Rush University Medical Center. In other words, though it may be a potential trigger for health issues, its impact has been blown way out of proportion. “Blue light has become the gluten of the sleep world,” Goldstein says with a laugh. “For this to get extrapolated to saying ‘blue light at night isn’t bad for you’ is a little bit of an extension,” Goldstein says.īut that doesn’t mean blue light is evil. Taken together, Goldstein says these conditions mean the study’s results apply only to a very narrow set of circumstances and metrics. They also kept light levels dim, regardless of color, which may not reflect the bright lights of electronics.Īnd finally, though mice are frequently used in sleep research, Goldstein notes that since the rodents are nocturnal, they may respond differently to light than humans do. The researchers looked specifically at cones in the animals’ eyes, which detect color, instead of melanopsin, which senses light and is central to the issue of melatonin secretion. Cathy Goldstein, a sleep specialist at Michigan Medicine. And there are additional caveats to this particular paper, says Dr. Does the new study change that theory?Īnimal studies should always be taken with a grain of salt, as they often do not translate directly to human behavior. IPad readers started producing melatonin 1.5 hours later than usual the next day, and experienced REM sleep-the phase during which dreams occur and memories are consolidated-once they conked out, the study found. One highly cited study from 2014 showed that using a blue-light-emitting iPad before bed suppresses melatonin, while reading a traditional book does not. Melanopsin, the pigment that helps eye cells assess light brightness, is particularly sensitive to shorter, cooler wavelengths like blue light, which some research says means blue light may affect the body more dramatically than other hues. Studies have suggested that blue light is an especially powerful melatonin suppressant. Nighttime light exposure can confuse this process, suppressing melatonin production and keeping you up longer.
This process is dependent upon melatonin, a hormone secreted when it’s dark outside. The most obvious circadian rhythm is the one that drives you to be tired at night and alert during the day. Your body is dictated by its circadian rhythms, a set of time-dependent physical, mental and behavioral shifts. Why is blue light thought to disrupt sleep?