How Does Blue Light Affect Sleep?

Due to their energy efficiency, fluorescent bulbs and LEDs have taken over the industry of lights. Today, these lights can be found in everything from television, e-books to smartphones and home lights. However, while we save energy with the use of these lights, we might also be hurting our quality of sleep. So, in this article we’ll look at how does blue light affect sleep and what we can do to reduce its effects.

how does blue light affect sleep

First of all, not only blue light affects your sleep, but the amount of light you’re exposed to overall. That includes artificial light and sunlight. It’s due to our body’s biological clock that works in circadian rhythms. These rhythms control various physiological processes in your body, including sleeping and eating patterns, hormone production and cell regeneration.

The natural light of the sun sets your circadian rhythm in sync with the day and night patterns of the outside world. The retina detects light and it sends signals to the hypothalamus area of your brain to start producing hormones that wake the body up and increase the brain’s alertness. In particular, it increases cortisol. And when the opposite happens, when it starts to get dark, the hypothalamus starts sending sleep-inducing hormones, such as melatonin, which prepares your body for sleep.

As you increase your exposure to artificial light, your body’s circadian rhythm becomes confused. The retina is detecting light at any time of day, so the body’s natural clock doesn’t know when to prepare for sleep. This makes it more difficult to fall asleep and it also affects your REM sleep, so you wake up feeling sleepier even if you’ve slept enough hours.

When your circadian rhythms are out of whack, it can have significant harmful effects on your health. It can create problems with cardiovascular, immune and metabolic systems. It can also affect your mood and cognitive function. As a result, you might feel, think and perform below your best.

Blue light creates a two-fold problem. First, it interferes with your natural rhythms and second, it suppresses the production of melatonin.

3 Ways Blue Light Is Affecting Your Sleep

Melatonin Suppression

how to reduce blue light exposure before bedtime

Blue light produces shorter wavelengths than other forms of light. And humans display peak sensitivity to this light, resulting in greater effect on our circadian clock and melatonin suppression.

One recent research studied 12 participants, which read books on an iPad for 4 hours before going to bed for 5 consecutive days and then they followed the same regimen for 5 days but with printed books.

The result of this research showed that when participants were reading on a light-emitting iPad, they had reduced secretion of melatonin, delayed circadian rhythm and they were less rested and less alert the morning after.

Other scientific studies have found that blue light suppresses melatonin production twice as much compared to other light wavelengths.

It Has Higher Color Temperature

On top of that, blue light has higher color temperature, which prevents body’s temperature from dropping during the night. But lowering body temperature is one crucial element of the body preparing for sleep. And if the body temperature at night stays at its daytime levels, it can disrupt the person’s normal circadian rhythms.

Suppresses Delta Brainwaves

ways blue light is affecting your sleep

Other studies have also found that blue light suppresses the sleep-inducing delta brainwaves. Instead, they increased alpha brainwaves, resulting in more alertness.

How To Reduce Blue Light Exposure Before Bedtime?

In modern times it’s impossible to stop using artificial light altogether. However, it is possible to limit your exposure to it.

  1. The best solution is to avoid your digital devices before going to sleep. Shut them off about 30 or 60 minutes before going to bed. And the closer you get to your bedtime, try choosing less interactive media consumption. For example, social media and video games are especially disruptive for sleep.
  2. Also, keep in mind that degree and intensity of blue light matters. Having your head buried in your phone has a greater effect than relaxing in front of a TV. So, it’s especially important to keep your smartphone away from the bedside.
  3. For those who just can’t turn off their digital devices, dim the brightness on your devices. There are also different apps that work to reduce blue light exposure during dark hours. Some smartphones even include these filtering apps as part of their operating systems. These apps work by scheduling the light to shift to warmer wavelengths in the evening hours and switch back to bright, shorter wavelengths in the morning hours.
  4. You can find similar applications for your computer. For example, Flux is free software that works on the same principle. It adjusts to the time where you live and then reduces the brightness of your computer screen in the evenings and increases it in the mornings.
  5. You can also block blue light exposure during evening hours by using special glasses that block blue light wavelengths.
  6. Another way to manage blue light exposure is to install lighting in your bedroom that is made to sync with our circadian biology. Some of the more advanced LED light bulbs are designed to reduce blue wavelength light at night and increase alertness-boosting light in the morning.

Final Words

In the modern age of technology, we live in a lit up world with light everywhere we turn. However, being more informed about the effects of blue light can help you protect your health and sleep. So, if you limit your blue light exposure before snoozing away on a pillow, you’ll be sleeping better, waking up less, waking up rested and functioning at your best during the day. There are different ways you can do this, from turning off your devices before bedtime to using blue light filtering glasses.

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