{"id":915,"date":"2018-06-03T12:00:37","date_gmt":"2018-06-03T10:00:37","guid":{"rendered":"https:\/\/britishdailynews.co.uk\/?p=915"},"modified":"2018-06-01T12:17:24","modified_gmt":"2018-06-01T10:17:24","slug":"the-truth-about-blue-light-does-it-really-cause-insomnia-and-increased-risk-of-cancer","status":"publish","type":"post","link":"https:\/\/britishdailynews.co.uk\/?p=915","title":{"rendered":"The truth about blue light: does it really cause insomnia and increased risk of cancer?"},"content":{"rendered":"

L<\/span><\/span>ong attached to visions of clear skies and calm seas, the colour blue historically could not be more welcome, refreshing and natural. Yet, because of the proliferation of blue-emitting LEDs in our artificially lit lives, blue light has come to represent bleary eyes, sleeplessness and the poor health associated with disruption of the circadian rhythm.<\/p>\n

Of the spectrum of lightwaves emitted by the sun that our eyes can detect, it is the shorter \u201cblue\u201d ones that get reflected and bounced around most by the molecules in the Earth\u2019s atmosphere. They are the reason the sky is blue. So why is blue light apparently so bad for us? Earlier this month, a\u00a0study<\/a>published in The Lancet Psychiatry looked at data from 91,105 middle-aged people and found that those with disrupted sleep patterns were more likely to have depression or bipolar disorder. The worst affected were described by one of the authors of the paper, Professor Daniel Smith at the University of Glasgow, as those with \u201cvery poor sleep hygiene \u2013 people on their mobile phones at midnight checking Facebook or getting up to make a cup of tea in the middle of the night\u201d. He reiterated the now common advice from sleep experts: switch off electronic devices an hour before bedtime.<\/p>\n

In March,\u00a0the chief medical officer, Sally Davies, advised caution<\/a>\u00a0in using devices emitting blue light while more research is done into its potential harm. Then in April researchers at the\u00a0Barcelona Institute of Global Health<\/a>linked increased risks of breast and prostate cancers to blue light exposure at night (an association was found, but whether the light exposure caused the cancers through circadian disruption is unknown). What we do know is that undimmed LED screens and lamps give off more blue light than traditional light sources, such as incandescent lightbulbs. And we are using backlit devices more than ever, whether checking social media and bank balances or grappling with heavy workloads, right up until lights out.<\/p>\n

The reason manufacturers have switched to brighter LED lights is efficiency. With traditional incandescent lightbulbs, says\u00a0John O\u2019Hagan<\/a>\u00a0of Public Health England\u2019s centre for radiation, chemical and environmental hazards, \u201c95% of what was produced was heat, and only 5% was light.\u201d As well as staying cooler, LED screens have the added benefit of being thinner, lighter and longer lasting, with stunning colour resolution.<\/p>\n

One indication of nagging worries about blue light is the increasing availability of anti-blue-light products \u2013 including\u00a0beauty treatments<\/a>claiming to protect skin from the light from phones and laptops, and anti-blue light lenses. In lab experiments, high exposure to blue light has been shown to damage animal retinas, but there\u2019s no evidence that current levels of exposure are harming humans\u2019 eyes. \u201cThe hype around the blue light hazard has got a bit out of control,\u201d says O\u2019Hagan. An advert by Boots Opticians claiming that blue-light filtering lenses could protect consumers from retinal damage, eye strain and fatigue\u00a0was banned by the Advertising Standards Authority in 2015<\/a>. When researchers test the blue-light levels in devices, says O\u2019Hagan, \u201cthey don\u2019t come anywhere near the international exposure limits even for prolonged viewing, and are only a fraction of what you\u2019d get just walking outdoors on a cloudy day.\u201d Working on his laptop, he says, is \u201ctrivial compared to me walking outside and looking up at the sky \u2013 not at the sun, just the sky.\u201d If humans were damaged by blue light exposure per se, we would have known about it long before LED screens dominated our lives. \u201cThere\u2019s still an awful lot that we don\u2019t know about this,\u201d he concedes, \u201cbut I\u2019m fairly convinced blue light is not causing any injuries as such.\u201d<\/p>\n

It is blue light\u2019s role in governing circadian rhythms that poses greater concern for public health. \u201cIf you go back in time,\u201d says O\u2019Hagan, \u201cas soon as the sun went down you went to bed, and got back up again when the sun came up. It isn\u2019t natural to extend your day with artificial lighting. People are also doing activities in the evenings they wouldn\u2019t have done even 20 or 30 years ago and that stimulation may be having far more effect than the light itself.\u201d<\/p>\n

Not that long ago, he says, \u201cyour television was a relatively small device in the corner of the room. Now you\u2019ve got a TV completely filling the wall; you are immersed in it. We don\u2019t know what the impact of that is and maybe it\u2019s not a problem at all. But we need some research doing on it.\u201d<\/p>\n

\u201cBlue light is not sinister,\u201d says Stuart Peirson, of the sleep and circadian neuroscience institution (SCNi) at Oxford University. \u201cYou get changes particularly in the blue part of the spectrum around dawn and dusk and so our bodies have evolved to be able to detect these changes, because they are what\u2019s important for setting our clocks. It\u2019s just that we\u2019ve subsequently invented devices that emit light and we\u2019ve filled our environment with them and made them addictive. If you go to bed at night and stare at your bedside lamp for 10 minutes, that will shift your clock, it\u2019s just that nobody does that.\u201d<\/p>\n

The focus on blue light began, he says, \u201cover 15 years ago, when we discovered there is a type of photoreceptor in the eye that detects light, but for circadian responses rather than visual responses.\u201d These include, he says, \u201csetting the circadian clock, regulating sleep and alertness, and also things like hormone responses such as melatonin.\u201d So as well as our visual photoreceptors, known as rods and cones (rods for night sight and cones for bright light and colour vision), we also have photosensitive retinal ganglion cells for circadian responses, and these are particularly sensitive to blue light.<\/p>\n

\u201cBut what we\u2019ve subsequently learned is that the rods and cones [which are sensitive to a spectrum of light frequencies] also help regulate the circadian responses, while the photosensitive retinal ganglion cells also work as light meters. The photosensitive retinal ganglion cells don\u2019t exclusively absorb blue light, it\u2019s just that they are better at absorbing it than, say, red light. If you cut out blue light, says Peirson, \u201cyou\u2019re still getting activation of the circadian system, albeit less.\u201d<\/p>\n

A cleverer way to tackle the problem, if you\u2019re not prepared to lower the house lights and give devices a miss towards bedtime, \u201cis to change the colour temperature of the display \u2013 how warm or cool it looks.\u201d Frustratingly, the only study Peirson knows of into the efficacy of doing this, using software called\u00a0f.lux<\/a>, was inconclusive. \u201cBut in fact just dimming the brightness will make a difference,\u201d says Peirson. \u201cThe night mode that many devices offer makes the display dimmer. Even if you don\u2019t have night mode, dimming LED lighting by 50% would be less bright to those ganglion cells than a fluorescent or incandescent light.\u201d<\/p>\n

Peirson is taken with an idea mooted by a colleague of his from Harvard, that in many ways, light is like a drug. \u201cIt can be used for both beneficial and harmful purposes. The key point is knowing when we need it and in what dose.\u201d<\/p>\n

Is blue light also the reason we get eye strain or tired eyes after prolonged computer use? John Lawrenson, a professor of clinical visual science at City University of London, isn\u2019t convinced. In a review of robust studies into blue light-blocking lenses, he found \u201cvery little in terms of significant differences in satisfaction with blue light-blocking lenses and standard lenses.\u201d This is partly because the lenses can only block a fraction of the blue light, but also, he says, the new term \u201cdigital eye strain\u201d can have many components to it \u2013 wearing the wrong glasses, dry eyes, or just sitting in front of the computer too long.<\/p>\n

Children\u2019s eyes are more sensitive to blue light, because, says O\u2019Hagan, \u201cas we age our blue light vision decreases. By the time you get to about 20 your blue light vision is rubbish.\u201d Overall, however, most people are not affected by any of these issues. \u201cSome people are, know they are and therefore should probably be switching devices off at least an hour before they want to go to sleep. It may have nothing to do with blue light. It\u2019s just light, staring at it and keeping stimulated. For those who do have problems, did they have problems before? Are they particularly sensitive to the light? We don\u2019t know.\u201d<\/p>\n

And of course eyes differ, as do circadian rhythms; there are not only larks and owls, but an entire spectrum in between. \u201cThe best thing people should do,\u201d he says, \u201cis get out at lunchtime. There\u2019s a lot of evidence that the light you get in the evening is less important than the dose of bright light you got at lunchtime. And it gives you exercise and makes you feel better.\u201d And while the internet is extremely useful, \u201cit\u2019s important for people to stop and do nothing for a while. If you want good sleep, you need to prepare for sleep.\u201d<\/p>\n

source:https:\/\/www.theguardian.com\/lifeandstyle\/2018\/may\/28\/blue-light-led-screens-cancer-insomnia-health-issues<\/p>\n","protected":false},"excerpt":{"rendered":"

Long attached to visions of clear skies and calm seas, the colour blue historically could not be more welcome, refreshing and natural. Yet, because of the proliferation of blue-emitting LEDs in our artificially lit lives, blue light has come to represent bleary eyes, sleeplessness and the poor health associated with disruption of the circadian rhythm. […]<\/p>\n","protected":false},"author":2,"featured_media":916,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[11],"tags":[],"_links":{"self":[{"href":"https:\/\/britishdailynews.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/915"}],"collection":[{"href":"https:\/\/britishdailynews.co.uk\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/britishdailynews.co.uk\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/britishdailynews.co.uk\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/britishdailynews.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=915"}],"version-history":[{"count":1,"href":"https:\/\/britishdailynews.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/915\/revisions"}],"predecessor-version":[{"id":917,"href":"https:\/\/britishdailynews.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/915\/revisions\/917"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/britishdailynews.co.uk\/index.php?rest_route=\/wp\/v2\/media\/916"}],"wp:attachment":[{"href":"https:\/\/britishdailynews.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=915"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/britishdailynews.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=915"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/britishdailynews.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=915"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}