blue on the face: the effects of blue light on sleep | SBM

Matt Gratton, University of Kansas/Children’s Mercy Hospital

Besides temperature, light is the most important trigger our bodies use to regulate sleep and wakefulness. When the light is dim, our body releases a hormone called melatonin. This hormone tells the body that it is time to sleep.

Although the sun is the main source of bright light in our lives, it is not the only source. Electronic screens, which emit blue light, are another constant source. Exposure to blue light at bedtime can trick our bodies into slowing down the release of melatonin.

This light source is also associated with stimulating screen activities. Scrolling through social media, completing work tasks and watching captivating TV shows are too entertaining for our brains to shut down. Blue light and internet browsing before bedtime can negatively affect sleep. It can disrupt normal body rhythms, interfere with sleep, and impact overall health.

How using screens before bed affects sleep

Exposure to blue light at night can disrupt your circadian rhythm. The circadian rhythm is a natural process that is part of the body’s internal clock. It is the cycle of physical, mental and behavioral changes that the body goes through every 24 hours. This process repeats every day, creating a healthy loop when left undisturbed.

Excessive exposure to blue light before bedtime can prevent smooth transitions from one point in the cycle to the next. You may feel unsteady after a night’s sleep or wake up frequently throughout the night.

When melatonin production drops, the body may think it’s still daytime while you’re trying to sleep. It can make you feel more awake. You may want to stare at something on your phone screen until you feel tired. This has the opposite effect and only further disturbs sleep.

Prevent the negative effects of blue light on sleep

  • Turns off at sunset. Turn off all bright lights at least an hour before bedtime. Dim light does not prevent the production of melatonin.
  • Stop scrolling. If possible, avoid using screens 30 minutes before bed. Even phone screens emit enough blue light to affect melatonin production. Try lowering your screen brightness or using dim light to read a book or print instead of scrolling on your phone.
  • Relax. Create a relaxation routine 30-60 minutes before bed, if possible. During your relaxation, it is best to perform relaxing activities such as night hygiene, reading or stretching. Try doing them outside of the bedroom so your brain only associates your bed with sleep.
  • Block distractions. Keep your sleeping area free from excessive noise and light. Blackout curtains, sleep masks or white noise generators can be effective tools.
  • Waking hour. Pick a consistent wake-up time and stick to it. Wake up with enough time to have a full day and be ready for bedtime. This helps solidify your circadian rhythm and creates other sleep triggers for your body.
  • Night lights. Sleeping with bright lights can also disrupt natural sleep cycles. Instead, try using a dim night light or a red light. These can help keep you sleepy and ready to sleep.
  • Get bright light during the day. Expose yourself to bright lights early and often during the day. Spend time outdoors as much as possible. This promotes wakefulness during the day and drowsiness at night.

Exposure to blue light close to bedtime can have a disruptive effect on sleep. This can lead to poor sleep and daytime drowsiness. Following these steps and avoiding screens before bed can help you create better sleeping habits. Improving sleep can improve your mood, health, and ability to think clearly.

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