![]() If you’re really concerned about blue light exposure, then there are bigger fish to fry than smartphones and tablets. But, what about the blue light coming from our devices? For most of us, subdued lighting towards bedtime is going to be enough to make a difference. There is evidence that the bulbs we use can also impact on our circadian rhythms, and worse, affect our skin the way that the sun does, but this usually requires close, prolonged proximity.Ī lot of bright lighting is obviously going to be an issue, that’s often a problem for night shift workers, depending on their environment. You might opt for a warm light bulb that emits lower levels of blue light for your bedroom, and use an Awake & Alert bulb in the kitchen to get you going in the morning along with your first cup of coffee. There’s a Florida company called Lighting Science Group which offers a line of “biological” lighting. Turning everything off and sitting in a dark room is not something many of us will do. Marshall, “More commonly now they’re LEDs and these light sources have a lot of the potentially damaging blue, to the extent that I don’t use them.” “Until recently, we lit our homes with incandescent bulbs and they were relatively biologically friendly, in that there was very little blue,” says Prof. The paper Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans, found that exposure to room light before bedtime suppressed melatonin in 99 percent of individuals and shortened melatonin duration by about 90 minutes. The electric lights in our homes may be having a bigger impact than our devices. “When was the last time you got an after image from looking at your iPad? When you look at a light source, especially an LED, you’ve got that multicolored image on your retina which takes a long time to fade.” LED light bulbs may be worse than your phone “Light bulbs are much brighter sources,” explains Prof. The risk of damage has a great deal to do with power and brightness. If you actually do the calculations from the spectral emission of those things – it’s tiny.” “The big red herring here is smartphones. “By far and away the biggest exposure you’re going to get is from the sun – that is the biggest blue light hazard that you will meet in your lifetime,” says Professor Marshall. For damage to the eye, the peak wavelength for blue light is around 440nm, but the suppression of melatonin is higher, at around 460nm. We know ultraviolet (UV) is damaging and the blue range is closest to it. “We are seeing a much greater number of age-related macular degeneration patients, even back correcting for the aging population, so the risk factors are clearly changing,” explains Professor John Marshall, Frost Professor of Ophthalmology at the Institute of Ophthalmology in London, “If you look at cataracts there’s a very good correlation between the age of onset of cataracts and the degree of ultraviolet where you live in the world, that’s why people close to the equator tend to get their cataracts 5 to 10 years earlier.” Over exposure could be playing a role in the rise of cataracts and even blindness. There are also some scientists linking blue light to age-related macular degeneration, though the evidence doesn’t seem to be conclusive. Lack of sleep has also been linked with mood problems, anxiety and depression, and increased risk of accidents. Those examples are mostly related to long term night shift, or severe sleep disorders, but any disruption to your circadian rhythm can cause problems. When our circadian rhythms are thrown off researchers believe we are put at more risk of all sorts of things including heart attacks, obesity and type-2 diabetes, and various cancers. ![]() There are more serious health issues to consider if you aren’t getting enough sleep. Unsurprisingly, the ebook reader group reported feeling less tired in the evening, but they also reported that they felt more tired in the morning, despite having the same duration of sleep as the other group. ![]() On average, they took 10 minutes longer to fall asleep and displayed significantly less rapid eye movement (REM) sleep than the group reading printed books. The patients using the ebook reader showed suppressed levels of melatonin. The paper assessed two groups half read a normal printed book for four hours before bedtime for five consecutive nights, while the other group read a light-emitting ebook reader for the same period. “In the past 50 years, there has been a decline in average sleep duration and quality, with adverse consequences on general health,” so begins an illuminating paper entitled, Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness, based on research from Harvard Medical School, amongst other places. “In the past 50 years, there has been a decline in average sleep duration and quality.” ![]()
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