At BLUblox we like to bring you the latest peer reviewed science on light and health. In June 2020 a new study was released in Sleep Advances entitled “Interventions to reduce short-wavelength (“blue”) light exposure at night and their effects on sleep: A systematic review and meta- analysis”.
The study can be read in its entirety but we will walk you through the science and break it all down for you in this short article.
The paper starts off by talking about how blue light impacts circadian rhythms, making note that blue light between 450-480nm has the strongest influence on melatonin production and sleep. This range of light is very much in the blue range of the spectrum. Blue light runs from 400nm to 495nm. Blue light in this range has been shown to suppress melatonin secretion and increase neurocognitive alertness.
The paper then goes on to show that this is a real concern as most smartphones, televisions, computers and domestic light bulbs are lit by light emitting diodes (LEDs) that are enriched in short wavelength blue light at around 460nm. Evidence was then presented in this study to show that it has been demonstrated that evening exposure to LEDs can supress and delay melatonin secretion, decrease sleepiness, prolong sleep initiation and worsen sleep quality.
Interventions to correct this circadian mismatch are cited in the study which include the use of blue light blocking glasses. Blue light blocking glasses are amber/orange/red tinted spectacles that filter out the blue light that is disrupting our sleep. When worn 2-3 hours before bedtime subjects release more melatonin and get to sleep quicker.
During this meta-analysis a total of 14,771 references were identified in relation to blue light and circadian disruption. Out of these references 86 of the most prominent articles were selected for review and 12 were selected for a systematic review.
Amongst the 12 included studies, eight were RCTs, and four were before-after studies. A wide age range was selected from 16 to 49 years old and participants ranged from 6 to 21 per study. The studies used orange blue light glasses and a clear pair as a dummy pair.
In the twelve studies, eight of them showed a positive effect from wearing blue light blocking glasses after sunset and four showed no effect. Positive effects included better sleep quality, longer sleep duration and better sleep latency. This is amazing to see as nobody’s sleep regressed wearing blue light blocking glasses and a staggering 67% showed significant positive improvements to sleep across the studies. Of the four studies where there were no improvements the participants were generally very healthy and younger. Older participants and those with sleep issues noticed a significant improvement in sleep. This begs the question that blue light blocking glasses may be great at preventing the onset of sleep disturbances in already healthy people later in life, despite seeing no improvement in their sleep scores.
The studies that assessed and measured melatonin levels showed a strong increase in nocturnal melatonin levels when participants wore orange lens blue light blocking glasses.
The studies also showed that even exposure to small amounts of blue light was enough to suppress melatonin. This is why at BLUblox we stress the importance of keeping your blue light blocking glasses on from sunset until bedtime.
It is no surprise that this meta-analysis of the studies available on blue light and sleep found that when people wear blue light blocking glasses they often improve both sleep and melatonin levels. Wearing blue light blocking glasses for sleep (before bed) has the greatest impact on people who have underlying health issues that may impair their sleep. People who generally get a good night’s sleep and are considered healthy often don’t see a huge improvement in their sleep. This is unsurprising as they are already sleeping well so there is no space for improvement. Having said that we know that as we age sleep becomes a bigger issue, therefore we can hypothesize that for healthy sleepers to remain healthy sleepers it is best to block blue light after sunset by using blue light blocking glasses. Blue light blocking glasses will increase melatonin production which will keep healthy people healthy and preserve their sleep as they age.
Link to the study discussed can be found by clicking here
For more information on blue light and to get a pair of the best blue light blocking glasses in Australia check out BLUblox.com