Should we be blocking more than just blue light?

Blocking blue light has become more of a common phrase over the last months and year, but why?

In my previous articles on blue light see here (1), (2) you can understand why it is important to block blue light for melatonin and retinal protection purposes. Blue is uniquely able to stimulate melanopsin which becomes a key regulator in the sleep-wake cycle. Unlike the other Opsins in the eye (rhodopsin and photopsin), melanopsin does not assist in vision. Melanopsin is active in sending signals to the SCN (suprachiasmatic nucleus) which helps regulate the circadian rhythm. Using blue light at the “wrong time” sends the wrong signals into the brain. It is not just that however.

 Let us not forget that there is a key difference between blue light that comes from the screens in front of you and you indoor lighting and that which comes from the sun. Mainly, Sunlight all includes the regenerative and protective wavelengths of deep read and infrared – your electronic products do not.

Extracting the deep red and infrared elements from the lighting removes the regenerating and protective properties from the light and increases the proportion of blue light. This is not to say that blue light can’t have some positive effects, because it can. It can help with alleviation of short term sleep deprivation (3) both in terms of physiological and mental performance. It can help with skin issues such as dermatitis, eczema and psoriasis (4). The paper (4) showed that both red and blue light had a strong positive effect on psoriasis. Combining blue and red light in one treatment might be the best and I am currently looking into those models soon. These are short term benefits to illicit a specific response, not chronic use.



BLUE CYAN and GREEN

Blue, cyan and green all have an affect on melatonin levels. In fact they found that polychromatic light (light sources with different colours) had more of an effect on evening melatonin suppression than pure blue light (5). This shows you that when you put your evening lighting on, it is important for you to try to limit 3 main wavelengths – blue, cyan and green. We need to look past “just blue” and add in protection and blocking of Cyan and green.

Another report showed that if we just to removed Cyan from the light, there would be no difference to melatonin suppression that full spectrum light (6)

Research has been conducted looking at night shift workers where they wear goggles that block everything below 530nm in wavelength. They found that melatonin suppression by blocking everything below this was as a low as 6% (7)

We have heard about Melanopsin, which is primarily activated by blue wavelength of light. We have heard that polychromatic wavelengths that contain wavelengths other than just blue are worse at suppressing melatonin so should we be blocking more than just blue?

Here in Norway right now  we find ourselves with a bit of an odd situation. We don’t need evening lighting (unless you are going to bed after 11), at the same time it is so bright outside. Is that affecting your circadian rhythm? There are some hypothesis that native Norwegians are used to this yearly cycle where their sleep pattern is markedly different between the cold dark winters and the warm and light summers. I have not looked into whether this means Nordic people are some what adapted to this absence of dark before bed. However, the physiological demands and keys that underpin a good sleep-wake cycle demand dark and light. So I will continue using my blue, cyan and green blockers and putting red into my home when I need to.

 The science is not debatable on light and melatonin suppression. The science is also not debatable on sleep deprivation and neurological disease, metabolic disease and even some cancers. So I will definitely continue to prioritise my sleep quality by using my blocking glasses! Even more so as I age because my sensitivity light will reduce.

AS YOU AGE, YOUR SENSITIVITY TO LIGHT LESSENS, IT IS VITATLY IMPORTANT THAT YOU KEEP THAT SENSIVITY HIGH BY BLOCKING SOME LIGHT SOMETIMES AND GETTING BRIGHT LIGHT OTHER TIMES (8)

Hopefully I can encourage you to invest in your light health.






REFERENCES:
1. https://lighttherapy.no/blogs/news/the-secret-to-a-good-night-sleep

2.

3. https://www.frontiersin.org/articles/10.3389/fnins.2019.01366/full

4. https://pubmed.ncbi.nlm.nih.gov/21435024/

5. https://pubmed.ncbi.nlm.nih.gov/18075803/

6. https://pubmed.ncbi.nlm.nih.gov/30821188/

7. https://pubmed.ncbi.nlm.nih.gov/23705821/

Picture source - https://www.dogonews.com/2018/10/15/blue-light-emitted-from-digital-devices-may-accelerate-blindness