New iOS feature promises users better sleep

Research suggests the blue-tinted light from smartphone screens interferes with users' ability to sleep.

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Apple's iOS 9.3 will offer a new feature called Night Shift, which aims to help users get a better night's sleep.

Night Shift will achieve this by adjusting the colour balance on users' iPad and iPhone screens to make the colours appear "warmer" after dark, establishing when the sun sets using the device's geolocation and internal clock.

In a May 2014 episode of US tech podcast Note To Self, host Manoush Zomorodi explores how artificial light in the form of digital screens interferes with users' circadian rhythms to negatively affect their sleep cycles.

In humans, the circadian rhythm most commonly refers to the body's natural waking-and-sleeping pattern, which is facilitated by sleep chemicals in the brain which take effect in dark surroundings.

Numerous historical and scientific studies suggest artificial light fundamentally interferes with these rhythms, tricking users' bodies into wakefulness at night.

Digital screens are believed to interfere with users' sleep cycles even more severely, as many users look at their smartphone screens in the dark just before bed to set alarms, or check the time when they wake up in the middle of the night.

"Every time you get that hit of light, it's like a hit of espresso," Lorna Herf, developer of mobile app f.lux, tells Zomorodi.

What also makes digital screens particularly damaging is that the light they emit is slightly blue-tinted, which more closely resembles midday sunshine than would light of a more yellow or orange hue, which could be read as sunset or candlelight.

By shifting the screens' colour balance to the "warmer" end of the spectrum at night, Apple aims to decrease the vigour with which digital screens can induce restlessness and insomnia.

Yet shifting colour balances after dark is not Apple's idea, nor is it a new one.

F.lux, for example, is an iOS app and computer program for Mac and Windows that has been shifting the colour balance on users' screens, in much the same way as Night Shift will, for over six years. It was initially released in 2009.