We live in a world of screens. But did you know that exposure to blue light from phones, tablets, and computers in the evening can delay your sleep by up to two hours? This surprising fact has prompted growing interest in blue light blocking as a tool for improving sleep quality. Research has shown that minimizing blue light exposure from devices can directly influence our ability to wind down and achieve restful sleep. By understanding how blue light affects your brain and sleep cycles, you can make simple adjustments that will significantly improve your overall sleep quality.
What Is Blue Light?
Naturally emitted by the sun, blue light is part of the visible light spectrum. It has a short wavelength and high energy and helps regulate our sleep-wake cycle by boosting alertness during the day. However, modern devices like smartphones, tablets, and LED lights emit significant amounts of artificial blue light, which we’re especially susceptible to in the evening. It’s also a component of white portions of the screen, so when you’re looking at something with a white background — such as a website or Word document — you’re getting exposed to plenty of blue light that’s part of the mix.
This artificial blue light can disrupt the body’s natural rhythms, making it harder to wind down for sleep. Moreover, small as they might be, those glowing screens can get overwhelming and overstimulating. As wellness expert Andrew Weil puts it, “A computer or TV screen may seem much dimmer than a light bulb, but these screens often fill your field of vision, mimicking the effects of a room filled with light.”
For those looking to quit or reduce alcohol, quality sleep is crucial for managing stress and cravings. Let’s take a closer look at the science behind the effects of blue light.
The Impact of Blue Light on Sleep
Blue light exposure in the evening confuses our internal clock, or circadian rhythm, signaling to the brain it’s still daytime and suppressing the sleep hormone melatonin. Research shows that even short bursts of blue light in the evening can suppress melatonin production by up to 85%, delaying the body’s natural sleep signals![1]
Studies also show that even when we eventually fall asleep after blue light exposure, the quality of that sleep is compromised. Blue light affects REM sleep, the deep stage of sleep that’s crucial for memory consolidation and emotional regulation. This restless sleep leaves us feeling unrefreshed in the morning (even if we spend adequate time in bed) and leads to mental fog and slower cognitive function the next day.
Blue Light: “Friend” or “Foe”?
That said, one of the tricky aspects regarding blue light is that in certain situations it can actually be helpful when it comes to sharpening focus and concentration. So how should we go about regulating our exposure to it?
Two recent studies reveal the deeper fallout of blue light exposure by showing how its effects on sleep translate to our mood, cognition, and energy levels during the day. Let’s take a closer look and see how the findings can help you revamp your sleep routine as you continue in your efforts to drink less or leave alcohol behind.
Blue Light: Implications for Cognitive Performance and Mood
A systematic review published in Frontiers in Psychology in 2022 set out to get the full picture behind its effects on sleep, mood, and cognitive performance.[2] By synthesizing evidence from numerous studies, the review aimed to clarify whether blue light is a friend or foe — particularly for young adults and athletes who often rely on both peak cognitive performance and restful recovery. The studies focused on healthy participants using blue light exposure through devices or light bulbs. Here’s what the authors found:
- Blue light increased evening alertness but led to poor sleep. About half the studies found that blue light reduced tiredness by improving alertness and reducing subjective sleepiness. However, blue light also decreased sleep quality and shortened sleep duration, with some studies reporting longer time to fall asleep (increased sleep latency) and less effective sleep overall.
- Cognitive performance improved initially, but the benefits came at a cost. Over half the studies showed improvements in tasks such as decision-making, attention, and memory after blue light exposure. Most also reported faster reaction times under blue light exposure. However, the benefits came at the cost of reduced sleep quality if exposure occurred late in the day.
In a similar way, well-being increased in the short term. Several studies noted improved mood and reduced irritability after blue light exposure. Once again, long-term overexposure to blue light, especially in the evening, led to a rebound effect and resulted in chronic stress over time.
Blue Light, Stress, and Alcohol Reduction
A 2021 study took a closer look at exactly how blue light increases stress.[3] The researchers set out to explore how different types of light exposure influence cortisol (our primary stress hormone) in the early morning. Healthy male participants were exposed to bright white light, blue light, dim light, or red light for one hour shortly after waking. The results showed that both bright light and blue light significantly increased cortisol levels compared to dim and red light.
However, while a boost of cortisol in the morning helps us feel alert and ready to tackle the day, excessive cortisol (especially in the evening) is a different story, especially as we try to set alcohol aside. Research shows that alcohol itself is known to temporarily boost cortisol levels, leading to chronic stress, cravings, and sleep disruption. It’s all about balance: keeping cortisol levels in check sets the stage for us to function at our best.
Improving Sleep: Tips for Reducing the Effects of Blue Light
To reduce the impact of blue light on the quality of your sleep, consider these strategies:
- Turn on night mode. Most smartphones, tablets, and computers have built-in night modes that reduce blue light. Set these to automatically activate in the evening to protect your eyes and prepare your body for sleep.
- Limit screen time before bed. Better yet, try to avoid screens for at least an hour before bedtime. Instead, opt for calming activities like reading a book (a paper one, not an e-reader!) or practicing meditation.
- Use blue light blocking glasses. If you can’t avoid screens, fall back on glasses designed to filter out blue light. Wearing these glasses a couple of hours before bed can prevent blue light from disrupting your sleep cycle.
- Invest in dim lighting. In the evenings, use dim, warm-toned lighting to create a relaxing atmosphere. This switch tells your brain that it’s time to wind down and help prepare you for sleep.
- Pair light strategies with stress management. Recognize that both alcohol and excessive blue light can elevate cortisol levels, increasing cravings and disrupting sleep. Combine these light management tips with stress-reducing practices such as yoga or deep breathing exercises to keep cortisol levels balanced.
Summing Up
Blocking blue light in the evening is a simple but highly effective way to improve your sleep quality and overall health. By regulating your circadian rhythm, reducing melatonin disruption, and promoting restful sleep, minimizing blue light exposure can help you wake up feeling more refreshed and mentally clear.
