For the past several years, people have heard that using computers, smartphones or tablets at night is bad for their sleep. Apparently, this has to do with baffling topics such as circadian rhythms, the pineal gland and the wavelength of blue light. Wha?
Simply put, with the rise of devices with screens, humans are getting more exposure to blue light after sunset, which throws the circadian rhythm “out of whack,” as a 2015 Harvard Health Letter put it.
A circadian rhythm, according to Science Daily, is “a roughly 24-hour cycle in the physiological processes of living beings…In a strict sense, circadian rhythms are endogenously generated, although they can be modulated by external cues such as sunlight and temperature.”
“The circadian biological clock is controlled by a part of the brain called the suprachiasmatic nucleus (SCN), a group of cells in the hypothalamus that respond to light and dark signals.” stated the National Sleep Foundation. Basically, light travels to the SCN in the brain, which lets other parts of the body know it is time to awaken.
“Study after study has linked working the night shift and exposure to light at night to several types of cancer (breast, prostate), diabetes, heart disease and obesity,” stated the Harvard Health article. “We do know that exposure to light suppresses the secretion of melatonin, a hormone that influences circadian rhythms, and there’s some experimental evidence (it’s very preliminary) that lower melatonin levels might explain the association with cancer.”
“When the SCN gets a dose of blue light, it tells the brain’s pineal gland to stop producing melatonin, the hormone that primes the body for sleep by signaling that it’s nighttime,” said Mariana Figueiro of the Lighting Research Center at Rensselaer Polytechnic Institute, in an article on FiveThirtyEight.com.
Much of this information is what prompted Apple to release Night Shift Mode for their products. Night Shift Mode is a feature that changes the color of the device screen to block more of the blue light. You can set the slightly yellowish-tinted screen to automatically appear starting at sunset every night by going to Settings -> Display and Brightness -> Night Shift. You can either turn it on manually or have it scheduled for certain times during the day or night. You can also adjust the warmth, with “More Warm” meaning less blue light.
The release of this feature generated a lot of buzz in the Apple community, even though the app f.lux has done the equivalent of Night Shift for seven years. However, Night Shift is designed to promote health and well-being seamlessly through Apple’s operating system. “Pleasant dreams,” coos Apple’s website solicitously.
But does Night Shift Mode really help?
An article on FiveThirtyEight pointed out multiple ways that devices might be affecting sleep, other than just with blue light. They point out that the urge to stay up is greater when you are on your device, whether you’re watching movies or checking emails. They also point out, “Screen time’s relationship with sleep can be a tricky subject to study, in part because technology keeps changing.”
One man, in an article for Tech Radar, claimed to have tracked his sleep both using Night Shift and turning it off before bed. Using a Fitbit Surge, he says he noticed “a small, but meaningful difference in my sleep quality over the course of my week-long test.”
I have been using Night Shift since the release, and it is definitely more relaxing on the eyes at night, although I haven’t noticed a tangible difference in sleep.
“Are screens keeping [people] up and then they’re excited, stimulated and alerted by light?” asked Lauren Hale, an associate professor at Stony Brook University School of Medicine. “Or is it just that people who are anxious or suffering from insomnia for some other reason choose to watch a movie?” FiveThirtyEight points out that both may be correct. “Insomniacs turn to screens late at night, which in turn leads to more sleep problems.”
Also, the affects probably vary for different people. Try Night Shift, f.lux or a similar technology for yourself, and let us know your results on validitymag.com.