Many of us reach for a computer or smartphone after getting into bed. In fact, the 2011 National Sleep Foundation’s Sleep in America poll found that 90% of Americans report using an electronic device in their bedroom within an hour of trying to fall asleep.

Unfortunately, screens on these devices can emit blue light that interferes with our natural sleep cycles. So, why does blue light adversely affect sleep?

How Does Blue Light Affect Sleep?


Blue light can affect your sleep – google image 

With the advent of artificial light and electronics, people are being exposed to increasing amounts of light before bedtime. While all types of visible light can affect circadian rhythms, blue light has the largest impact.

We get the most of our exposure to blue light from the sun. Blue light stimulates parts of the brain that make us feel alert, elevating our body temperature and heart rate. During the day, blue light can improve performance and attention, tuning our circadian rhythm and setting us up for a better night’s sleep after the sun sets.

Blue light suppresses the body’s release of melatonin, a hormone that makes us feel drowsy. While this may be helpful during the day, it becomes unhelpful at night when we’re trying to sleep. Being exposed to blue light in the evening can trick our brain into thinking it’s still daytime, disrupting circadian rhythms and leaving us feeling alert instead of tired.

Chronic misalignment of circadian rhythms can also lead to many negative health impacts, including metabolic disorders and mental health conditions such as depression. With the significant health consequences associated with exposure to blue light after dark, it’s important to understand the sources of blue light and ways to reduce the risks.

Blue Light Sources


Americans spend an average of 7 hours a day on electronic devices. That’s a lot of time staring at blue light. Worse yet, nine out of 10 Americans admit to reaching for an electronic device at least several nights each week shortly before bedtime. That could be an invitation for insomnia.

The light from your devices often appears white. But they can give off wavelengths in the range of 400 to 490 nanometers, which is blue light.

Indoor sources of blue light include:

  • Televisions
  • Smartphones
  • Tablets
  • Gaming systems
  • Fluorescent light bulbs
  • LED (light-emitting diode) bulbs
  • Computer monitors

Ways to Manage Blue Light

The simplest way to lower your exposure to artificial blue light is to turn off your smartphone, TV, and other gadgets well before bedtime. Other ways include:

  • Blue light-blocking glasses. They’re widely sold online. Amber or brown-tinted lenses may help best.
  • Cut back on screen time starting 2-3 hours before bed.
  • Dim the brightness on your devices. This is often called night mode or dark mode. It changes the background from white to black.
  • Install blue light-filtering apps on smartphone, tablet, and computer screens. They filter a lot of blue light from reaching your eyes without making it harder to see the display.
  • Swap light bulbs. LEDs give off more blue light than fluorescent bulbs. And both emit more blue light than energy-hungry incandescent bulbs, which are being phased out.
  • Use a dim red lightbulb as a nightlight. Red is the color that least affects your circadian rhythm.
  • Set an alarm for 1 hour before bed to remind yourself to quit using devices.

Source: sleepfoundation, webmd


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