How Blue Light Exposure at Night Disrupts Sleep and What to Do

What is Blue Light?

Blue light is a range of visible light wavelengths between 400-500 nanometers emitted from many digital devices like phones, tablets, and computer screens. It's also emitted naturally from the sun.

Blue light wavelengths stimulate receptors in our eyes that regulate our wake/sleep cycle. During the day, blue light exposure from the sun is beneficial and helps us feel alert. But excessive blue light exposure at night can throw off your body's circadian rhythms.

Blue Light Vs UV Light

It's important not to confuse blue light with UV (ultraviolet) light. UV light has shorter wavelengths and higher energy that can cause skin cancer and eye damage. Blue light from screens and devices is not the same high-energy light.

How Digital Devices Emit Blue Light

LED (light-emitting diode) and OLED (organic LED) screens found on most smartphones, tablets, computers, and TVs emit strong blue light. Fluorescent and LED lighting also emit some blue wavelengths.

How Blue Light Affects Sleep

Exposure to blue light wavelengths after sunset tricks your brain into thinking it's still daytime. This disrupts your circadian rhythms and suppresses natural melatonin production. Specifically, blue light affects sleep in the following ways:

Delays Your Body's Internal Clock

The blue light signaling to your brain keeps you feeling alert and awake for longer in the evening. This delays the timing of your circadian clock, making it harder to fall asleep at an appropriate bedtime.

Suppresses Melatonin

Melatonin is the hormone that controls sleep/wake cycles. Production of melatonin normally increases in the evening as exposure to blue light decreases. But blue light exposure from screens inhibits this rise in melatonin, delaying and disrupting sleep.

Impacts Sleep Quality

With inadequate melatonin and shifted circadian timing, blue light exposure before bed decreases sleep quality. It results in less restorative REM and deep sleep.

Causes Daytime Fatigue

Poor quality sleep and phase shifted circadian rhythms due to blue light at night leads to impaired daytime alertness and increased fatigue even after adequate time in bed.

Top Sources of Blue Light Exposure

The most common sources of blue light that can disrupt sleep include:

Smartphones and Tablets

The LED displays on mobile phones and tablets emit high intensity blue light. And people often use these devices right before bed.

Computer Screens

Desktop computer monitors, laptops, and other screens also use LED/OLED displays that give off blue light wavelengths.

TVs

The shift from cathode ray tube TVs to energy efficient OLED and LED TV screens has dramatically increased blue light exposure in the evenings in many homes.

Fluorescent and LED Lighting

Many modern energy-saving bulbs like compact fluorescents (CFLs) and LED lights emit some blue wavelengths and can impact sleep when used at night.

Digital Clocks

Even the simple digital clock on your nightstand can be a source of blue light disruption. Place clocks far from the bed or use low intensity settings.

Tips to Reduce Blue Light Exposure at Night

Use these tips in the evening and before bed to help minimize blue light from screens and devices:

Turn Off Screens 1-2 Hours Before Bed

Avoid using phones, tablets, computers, TVs, and other digital screens for at least an hour before bedtime. This allows natural melatonin production.

Use Blue Light Filter Settings

Enable night mode or blue light filter options on phones, tablets, and laptops. This reduces the amount of blue wavelengths emitted.

Wear Blue Light Blocking Glasses

Special glasses with amber colored lenses filter out blue light. Wear them in the evening if you have to be in front of screens.

Dim Bright Screens

Turn down the brightness significantly on any digital screens you use at night. Brightness intensitifies disruptive blue light.

Use Warm Tinted Light Bulbs

Swap out cool white lighting at night for bulbs with a warmer color temperature. Candle bulbs are a good option.

Avoid Overhead Lights

Use lamps or wall sconces instead of bright overhead lighting in the evening and when getting ready for bed.

Read a Paper Book

Curl up with an old fashioned paper book instead of reading on an e-reader which emits blue light. Or listen to an audiobook.

Other Tips for Better Sleep

Along with reducing blue light at night, here are more ways to improve sleep quality:

Keep a Consistent Sleep Schedule

Going to bed and waking up at the same times daily stabilizes your circadian clock for better sleep.

Make Your Bedroom Dark

Total darkness encourages melatonin secretion. Use blackout curtains or an eye mask to block out light.

Avoid Caffeine After Lunch

Caffeine has a long half-life and can interfere with sleep when consumed too late in the day.

Establish a Soothing Routine

Rituals like a hot bath, light yoga, or reading relieve stress for sounder sleep.

Keep Your Bedroom Cool

A slightly cool room temperature around 65F or 18C is ideal for sleeping.

Talk to Your Doctor

If you continue having sleep issues after trying to minimize blue light exposure at night, speak with your doctor. They can check for underlying medical problems and may recommend further assessment for sleep disorders like insomnia.

Your doctor may also suggest trying a melatonin supplement in the evening to help reset your circadian clock. This should be taken only under medical guidance.

The Effects of Blue Light on Sleep

In conclusion, blue light exposure from screens and devices in the evening and nighttime has significant detrimental effects on your sleep quality and circadian rhythms. But by being mindful of these effects and taking steps to reduce blue light at night, you can still get restful, uninterrupted sleep.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.