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How Does Blue Light Affect Sleep?

Eoin Mc Guinness
Posted by Eoin Mc Guinness on Nov 3, 2020 1:00:00 PM

Are your struggling to get a good night's sleep? Insomnia and other sleep problems can occur if you take in too much blue light at night. 

Is Blue Light Bad for Your Health?


Not all blue light is bad for you. During the day blue light helps keep you alert and focused. Blue light has been shown to improve a person's mood. It can be therapeutic for people suffering from depression or seasonal affective disorder (SAD). 


In contrast, too much blue light at night can negatively affect your health by causing sleep problems that may lead to heart disease, obesity and type 2 diabetes.

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Blue Light and Sleep


Taking in too much blue light at night can throw off your natural circadian rhythm. It can make it hard for your brain to distinguish day from night.

When it is dark melatonin secretion occurs and informs your body it is time to rest. Blue light prevents this from happening and triggers you to stay awake.


Your circadian rhythm controls your sleeping patterns.  When altered by blue light your sleep patterns change. This change is due to a reduction in melatonin. While all light can cause this reduction, blue light has more of an impact; especially, at night time.


A Harvard study underlines the dramatic affect of blue light on melatonin production. Researchers compared 6.5 hours of blue light exposure to green light.  The results revealed that blue light reduced the secretion of melatonin 2 times longer than green light. Blue light shifted circadian rhythms by 3hrs as compared to green light at 1.5 hrs.

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Items that Give Off Blue Light


Household lights, LED lights and various electronics give off blue light. Computers, cell phones and televisions can give off blue light. This is why many experts suggest avoiding these electronics a few hours before going to sleep.

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Ways to Avoid Blue Light at Night


Turning off your television and reading a book can be a great way to limit your exposure to blue light at bedtime. This assumes your reading light has an amber tint.


Sometimes though you may find you need to work on your computer at night or that you want to watch a movie before bed. If either is the case there are steps you can take to reduce the amount of blue light that you take in from electronic devices.


There are two ways to limit your exposure of blue light at night. The first is by installing an app on your computer or smart phone that filters out blue wave lengths at night. The second is by wearing glasses that filter out blue light.

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Do Blue Light Glasses Actually Work?


Not all glasses that filter out blue light are equal. A cheap pair of amber tinted sunglasses will filter out blue light but they cannot be used indoors because they filter out other colored light as well.


A good pair of blue light glasses retail for about €69. These glasses have been designed to work indoors. They protect your eyes from blue light exposure.  They should be used whenever you use technological devices; especially at night.


Studies have shown that people wearing blue light glasses in a lit space or using a electronic device produce the same amount of melatonin as those sitting in the dark. These studies have also revealed that blue light glasses can help improve sleep and enhance mental functions.



Topics: Tips How to Blue Light blocking