Blue Light Exposure – What is it?

The largest source of blue light is sunlight. However, high concentrations of blue wavelength light are also produced by smartphones, tablets, television, high-efficiency light bulbs and other digital devices. During the day, the blue light in sunlight signals our brain that we should be awake, and alert. When the sun sets and night falls, our body transitions with the earth in its own 24-hour circadian rhythm. Our circadian rhythm controls when we are most alert and productive during the daytime, and when we should be getting some sleep. The absence of blue light during the night signals our brain we should be resting.

The presence of blue light during these night hours is known for preventing the release of the hormone melatonin, which is associated with regulating biological rhythms and sleep cycles. Typically, leading up to sleep, the pineal gland (a pea-sized organ in the brain) is activated by optical darkness (lack of light). The gland then begins releasing melatonin and signals the physiological process that prepares the body for sleep. If you are exposed to enough blue light before bed, the gland can stop the release of melatonin, making it harder for the body to prepare for deep rest. It’s important to note that you don’t have to stare directly into the device to feel its impact, all you need is enough blue light to reach your eyes to feel the impact.

Blue light suppresses the production of melatonin for more than twice as long as any other light wavelengths. It also alters circadian rhythms by twice the degree. The combination of which has a significant impact on health and can lead to mood disturbances and compromise cognitive function. It is also known to create problems with the cardiovascular, metabolic, and immune systems.

Sources of blue light include;

  • The sun
  • CFL (compact fluorescent light) bulbs
  • Computer monitors, smartphones, and tablet screens
  • Flat screen LED televisions
  • Fluorescent light
  • LED light

What causes it?

How often do you fall asleep watching television, or browsing on your phone, tablet or laptop? If you’re like most Americans, this kind of device use has probably worked into your nightly sleep routine. The National Sleep Foundation estimated that 95% of adults use electronic devices before bed.

The exposure to light from your devices is interfering with your sleep, and you may not even realize it. There is growing evidence that nighttime exposure to artificial light can be destructive to your sleep by causing alertness and delaying deep sleep. Studies have shown that different wavelengths of light can have numerous effects on your body, and blue wavelengths specifically may exert a strong influence on the body’s circadian system.

According to a 2014 study that examined the effect of reading on an electronic device compared to a printed book, those who read on devices took longer to fall asleep, had less REM sleep, and had higher alertness before bedtime than those who read a paper book. Not only that, but those who read from a device were also sleepier in the morning and took longer to wake up.  Also, studies show that social media and video/app games are especially disruptive to sleep.

How long is too long of exposure before bed?

Studies have shown that the natural evening rise in melatonin is not significantly affected by 1 hour of bright screen light exposure. However, it is affected after 1.5 hours. After using blue light emitting devices for more than 1.5 hours people had reported feeling less sleepy. Their mental performance tests also showed improvements and their brainwaves showed increased alertness. Over the course of 5 days, their circadian rhythm was delayed by 1.5 hours. As a result, using electronic devices before bed led to people wanting to go to sleep later and later and sleep in later and later. For those needing to get up at a specific time for work, this leads to them being increasingly sleepy in the daytime.

Possible solutions

The amount of time Americans spend on screen technology overall has increased significantly over the past few years. You may even find it difficult to put down your device while winding down at night. Here are some suggestions to help with your blue light exposure.

  • Limit evening device use to one hour
  • Avoid looking at blue light emitting screens one to two hours before bed
  • Set your alarm to remind yourself to shut down your device use
  • Keep screens away from your face at night and dim the brightness on your device
  • Use LED light bulbs that are designed to minimize negative effects of blue wavelength light at night
  • Use dim red lights for night lights because red light is least likely to shift your circadian rhythm and suppress melatonin
  • Expose yourself to as much bright light as you can during the day; this will boost your ability to sleep at night, as well as your mood and alertness during the day
  • Utilize mobile apps that allow your phone to shift to warmer redder wavelength light in the evening. (Apple iPhone has “Night Shift” built-in)
  • Utilize a blue light filtering app or one that at least adjusts the light of computer to match the cycle of natural sunlight according to your location
  • Try reversing the print and text colors on your eReader so that the text is white and the background is black
  • Consider wearing blue-light filtering glasses or using blue light filters for screens

Why minimize your blue light exposure?

Quality sleep, with the right amount of time spent in each phase, is an essential fuel for life. Too much exposure to blue light impacts your ability to get deep sleep. Deep sleep is how your body repairs the vital organs that are keeping you healthy, including heart, lungs, immune systems, etc.  When your natural circadian rhythm is impacted by too much blue light before bed, you’re probably not getting the quality sleep you deserve. Aside from disrupting your sleep, blue light can also cause retinal damage with extended exposure. We depend on the process of light to pass through the eye to the retina where photoreceptors transform into an electrochemical signal for image formation and regulation of sleep-wake cycles. Try reducing your nighttime blue light-emitting electronic device use before bed to see if it results in the improvements in your sleep quality that you’re seeking.

Always seek the advice of a physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. This article is for informational purposes only and does not constitute medical advice; the Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment.