So I have heard that to much exposure to specifically blue light can make it harder to sleep but how?I mean it’s light and blue is seen as a calming color so how can exposure to to much blue light make it harder to sleep?
In: Biology
Our waking and sleeping cycles are regulated by a variety of factors.
One of those factors is the colour of the light that we are being exposed to. A natural lifestyle would mostly involve getting up when the Sun rises and going to bed when the Sun goes down.
The light from the Sun seems reddish at dawn and dusk but bluer during the middle of the day. Our brains are programmed to take those cues to determine when the day begins and ends.
Blue light from phones and other devices fools our brains into thinking that it’s still daytime.
Some studies have shown that exposure to blue light suppresses the secretion of the hormone melatonin, which is a critical hormone in regulating our sleep cycles.
Before the invention of screens, this was a non-issue, as the only naturally occurring source of blue light was the sun. It is theorized that this is _why_ melatonin is impacted by blue light – when the sun is out (and we need to be awake) melatonin is suppressed, and when the sun sets (and we should sleep) that suppression stops. We evolved to use the wavelengths that only the sun produces, as opposed to light from fires, to align with that need.
The problem in modern times is that many of the devices we use day and night produce blue light. Our TVs, computers and phones are blasting us with blue light, which is impacting our body’s ability to know when it should be awake vs. be asleep.
There’s a hormone called melatonin that’s produced in our brains that’s partially responsible for regulating our sleep-wake cycle. Melatonin makes us sleepy and prepares our bodies for sleep. Exposure to blue light suppresses the production of melatonin in our brains, so that signal for our bodies to get ready for sleep and for us to feel sleepy is missing or weaker than it should be.
There’s a hormone called melatonin that’s produced in our brains that’s partially responsible for regulating our sleep-wake cycle. Melatonin makes us sleepy and prepares our bodies for sleep. Exposure to blue light suppresses the production of melatonin in our brains, so that signal for our bodies to get ready for sleep and for us to feel sleepy is missing or weaker than it should be.
Blue light can affect sleepiness because it interferes with the body’s natural sleep-wake cycle, also known as the circadian rhythm. Our bodies have an internal clock that helps regulate when we feel awake and when we feel sleepy.
Exposure to blue light, especially from electronic devices like smartphones, tablets, and computers, can trick our brains into thinking it’s still daytime. This is because blue light suppresses the production of melatonin, a hormone that helps regulate sleep. When our brains perceive blue light, they interpret it as daylight, which can make us feel more alert and less sleepy.
If we’re exposed to blue light in the evening, such as when using electronic devices before bedtime, it can disrupt our natural sleep-wake cycle by delaying the onset of sleepiness and making it harder to fall asleep. This can lead to sleep problems like insomnia or poor sleep quality.
To minimize the effects of blue light on sleepiness, it’s helpful to limit exposure to electronic devices with screens, especially in the hours leading up to bedtime. Some people also use blue light filters or wear special glasses that block blue light to reduce its impact on sleep. Additionally, creating a relaxing bedtime routine and optimizing the sleep environment can help promote better sleep.
We have special cells in our eyes that aren’t related to vision called intrinsically photosensitive retinal ganglion cells or ipRGC’s, which detect a very narrow band of colors of light. These cells are in lots of different animals, including insects, so they evolved first hundreds of millions of years ago, when all life was in the ocean. When you get deep enough in the ocean, the only light that can penetrate is blue, specifically light around 475nm in wavelength, which is like a sky-blue or cyan color. White light is a mix of colors, but you can’t tell whether a white light source contains a lot or a little of any specific color just by looking at the light.
Our internal clocks are largely set by the signals that these cells produce. During the day and especially in the morning, getting light in that color range tells your body that it’s daytime. At night, if those wavelengths are absent, your body can produce melatonin and help you sleep.
Since when these cells evolved, blue was the only color of light available to tell day from night, that was what they evolved to detect. Before artificial light, there was never an issue because fire doesn’t have a lot of blue in the light it produces. With the electric light, we started to move indoors during the day more and more, meaning we usually don’t get *enough* blue light to tell our clocks it’s daytime. With the switch to LED, there’s more blue light in the typical white lights we use, which has made it harder to avoid blue light at night.
What you can do about this for yourself is make sure to get outside as early as possible in the day to get good light for a half hour or so to set your circadian clock, and starting from about 3 hours before bed, dim your lights as much as possible.
Here’s a quick explainer video that might help: [https://youtu.be/5wAr0KYoOxc](https://youtu.be/5wAr0KYoOxc)
Nightfall makes us sleepy, artificial blue light makes our brain think it’s still daytime so we don’t get sleepy
Does watching TV have an effect? I do not watch TV during the day but do turn it on when I go to bed. There is nothing good on despite having 200+ channels. I get bored after 15minutes and fall asleep.
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