• Too much blue light exposure—especially before bed—can prove harmful to your sleep cycle, as it will make you feel and stay awake.
  • Blue light is made up of shorter wavelengths, of which have more energy; researchers have found that blue light is more harmful than other colors like red or green light.
  • More specifically, blue light suppresses melatonin, which plays an important role in your sleep cycle—this suppression is what causes you to have difficult falling asleep.
  • Additionally, blue light can cause damage to your vision, contribute to the development of certain cancers, and increase your risk of depression.
  • You can protect yourself from these harmful effects by limiting your blue light exposure at night and capitalizing on light exposure during the day instead.

You come home after a long day of work and can’t wait to relax. Within minutes of walking through the door, you’re sinking into your favorite couch—and naturally, pulling up Facebook. For the next 30 minutes you’re scrolling: looking at status updates, swiping through profiles, and editing your own. Soon enough, you grow bored and open Instagram instead. This pattern repeats itself as you check each social media account. When you’ve finally covered all the bases, it’s time to sort through your emails. Some 20 minutes later, you’re finished—and exhausted. You shut down your iPad and climb into bed, excited to rest. But when you shut your tired eyes, you can’t seem to doze off. Why?

What Exactly Is Blue Light? How Does It Affect My Sleep?

Let’s try to keep this as simple as possible: different light rays have different wavelengths, which contain more or less energy. Those on the red end of the visible light spectrum have longer wavelengths and less energy, while those on the blue end have shorter wavelengths and more energy. Basically, too much exposure to these high-energy rays can prove harmful—for example, it can make us feel alert and awake, even when we’re tired, according to the National Institutes of Health. This makes it more difficult to fall asleep, which of course, has negative implications on our health.

Researchers from Harvard observed this harmful effect of blue light in an experiment that exposed participants to 6 ½ hours of blue light and another 6 ½ hours to green light. They found that blue light suppressed melatonin for twice as long as the green light. Melatonin plays an instrumental role in our sleep cycles—and when the release of it is delayed, it takes longer for you to fall asleep. This study highlighted these effects and further stressed the importance of protecting yourself from too much blue light exposure.

How Else Can Blue Light Affect My Health?

The devices we’re on all day, every day—our phones, iPads, laptops, and computer monitors—all use blue light. And we’re suffering as a result. In addition to affecting the quantity and quality of your sleep, blue light can contribute to a few other health risks:

  • Low melatonin levels may play a part in the development of breast and prostate cancer.
  • The blue light exposure in the evening, which causes us to get less sleep, can put us at an increased risk of depression.
  • Anterior structures of the human eye (like the cornea and lens) block UV rays from reaching the retina. However, blue light passes through these structures and reaches the retina, which can cause serious eye damage.

Protect Yourself From Blue Light: 4 Tips

It’s important to note that not all blue light is bad. Research shows that a healthy level of blue light exposure can boost alertness, improve your memory and cognitive functions, and elevate mood. Additionally, people are exposed to blue light rays when they undergo light treatment which helps to alleviate the effects of seasonal affective disorder. That said, too much blue light can prove harmful—especially before bed. Here are a few tips for protecting yourself:

  1. Use dim red lights for nightlights—the red light will suppress melatonin the least.
  2. Two to three hours before bedtime, turn off your screens.
  3. Invest in blue light-blocking glasses or screen covers.
  4. Try to get lots of light exposure during the daytime—this may help you to sleep better at night and lift your mood. It’ll also keep you sharp during the day.