What effect does light’s spectrum have on sleep? Exposure to blue wavelengths of light in the evening hours can significantly delay the release of melatonin, and shorten the hormone’s duration. Both of these changes disrupt normal circadian function and sleep. While all light can be disruptive to sleep when used at the wrong times, cooler temperature light—especially blue light—is particularly harmful to sleep and to circadian rhythms. Light at the warmer end of the color temperature spectrum has a less significant impact on sleep and circadian function. Digital devices emit high concentrations of blue light. Night Shift aims to replace some of that cool, sleep-disrupting light with warmer light in the evenings.
Night Shift isn’t the first app to provide this kind of sleep-protective light adjustment. F.lux and other apps have offered similar services for years. But Apple’s inclusion of Night Shift to its latest upgrade makes this technology more widely available and more easily accessed. Given the attention that inevitably comes with Apple releases, Night Shift’s debut also raises the profile of the issue of artificial light exposure, and the potential hazards of blue light.
Adjustments to the characteristics of light emitted from mobile devices stand to be legitimately valuable to sleep. But they will not solve the problem of excessive and ill-timed light exposure, and the negative consequences to sleep and overall health. We all need to look at the light in the entire sleeping environment, and replace these light sources with ones that are sleep friendly. Everyone that uses Night Shift should have specialty sleep friendly bulbs in their home and vice versa. There is a good bit of new technology out there to review. This is a growing problem that has existed for some time, well before the proliferation of smartphones and other mobile devices. Light poisoning is a pervasive environmental problem and public health challenge, one that continues to be sorely underestimated. I continue to believe that lights should come with a warning health label for everyone, light is medicine, it is that simple, so we all need to understand the side effects of this stimulus to our health.
So, kudos to Apple for Night Shift. Let’s hope it’s one part of a much bigger, badly needed shift in the way we treat and manage light in all areas of our lives, for the sake of sound sleep and good health.
Michael J. Breus, PhD
The Sleep Doctor™ www.thesleepdoctor.com