Since 2017, Apple has introduced Night Shift into its products. This setting aims to minimize the adverse effects of blue light emitted by phones, tablets, and other devices. However, some studies do not recognize the effectiveness of Night Shift.
Melatonin – a hormone that plays a significant role in sleep. When the sun rises and you are exposed to bright light, your body suppresses the production of melatonin, helping you feel awake. The color temperature of light also changes throughout the day. Daylight exists at around 5600 Kelvin, appearing blue. Sunset seems much warmer at around 3000 Kelvin. This natural color change, combined with gradually decreasing brightness, signals our bodies to start producing melatonin, making us feel sleepy.
Phone screen in Night Shift mode.
The phone screen at its default setting has a color temperature of 5600 Kelvin. The artificial light from phones, also known as blue light, inhibits melatonin production, disrupting our sense of sleepiness.
However, according to Rohan Nagare, a sleep researcher who shared on the VOX channel, some studies do not acknowledge the effectiveness of Night Shift.
Research examined Night Shift set to a warmer temperature – meaning the screen colors are shifted strongly toward the warmer end of the spectrum – and also Night Shift set to less warm – meaning only a slight warm shift. The results showed that both modes inhibit melatonin, but at slightly lower levels than when Night Shift is off, and there were no differences between the two modes.
And while this might sound like Night Shift is ineffective, light spectrum is just one aspect. Scientists assert: “Not only the light spectrum but also the duration and intensity of light entering the eyes are major factors affecting sleep quality.“
If you use your phone at night, you shouldn’t worry too much if it’s for 20 or 30 minutes. But if you exceed that, planning to watch movies every night or binge three episodes of a Netflix show, it will accumulate a significant biological dose that delays your sleepiness every day.
That concerns duration, but another issue to consider is the intensity of the light. In fact, a light source closer to the eyes is four times more intense than the same light source at double the distance from you. If you are about to receive 1000 lux of light into your eyes, it really doesn’t matter if it’s a warm or cool source; that level is too high for your eyes.
Based on these findings, to protect your eyes, reduce screen brightness, hold your phone farther from your eyes, switch to warmer colors, and limit screen time each evening.
