How Blue Light Disturbs Sleep
If you’re like more than 80 percent of Americans, one of the last things you do each day is look at a screen. Whether you are looking at a smart phone, tablet, computer or television screen, blue light is being emitted that increases alertness to the brain, which can really mess with your natural sleep and awake cycle. Here, we will go over what you need to know about blue lights and how making some minor adjustments can give you better night of sleep.
What is Blue Light?
Blue light, also known as high energy visible (HEV) light, is a type of light with short wavelengths emitting a higher energy. The sun is a natural source of blue light, signally our bodies when to be more alert. The cycle of light and dark created by sunlight synchronizes the body’s natural “clock” to the 24-hour day. However, blue light is also emitted through screens of electronic devices and therefore also send signals to the body to be alert.
What is Circadian Rhythm and Why is it Important?
Circadian rhythm is roughly a 24 hour cycle in the physiological processes of living beings that include patterns of brain wave activity, hormone production, cell regeneration, growth in children and other biological activities.
Circadian rhythms are important in determining the sleeping and feeding patterns of all animals, including human beings. It acts as an internal clock, running in the background of your brain and cycles between sleepiness and alertness at regular intervals. It’s also known as your sleep/wake cycle.
How Blue Light Disturbs Circadian Rhythm
Normally, melatonin levels rise in the evening and stay elevated throughout the night, promoting sleep, a natural part of circadian rhythm. However, blue light suppresses melatonin by penetrating deep into the eyes. This fools the brain into thinking that it is daytime and makes us feel more alert when we should be feeling sleepy, disturbing circadian rhythm.
Other Possible Health Complications Related to Blue Light Use
- Studies have shown that too much exposure to blue light can damage light-sensitive cells in the retina. (Because nearly all visible blue light passes through the cornea and lens and reaches the retina.) This causes changes similar to those of macular degeneration, which can lead to permanent vision loss. This has many health care professionals concerned about possible long-term effects of blue light on eye health.
- A Harvard study showed a possible connection to diabetes and possibly obesity. The researchers put 10 people on a schedule that gradually shifted the timing of their circadian rhythms. Their blood sugar levels increased, throwing them into a prediabetic state, and levels of leptin, a hormone that leaves people feeling full after a meal, went down.
- The flickering and glare created by blue lights can reduce visual contrast and may be a reason for physical and mental fatigue, along with digital eyestrain. Symptoms of digital eyestrain, or computer vision syndrome, include blurry vision, difficulty focusing, dry and irritated eyes, headaches, neck and back pain.
- Harvard researchers have linked working the night shift and exposure to blue light at night to several types of cancer (breast, prostate) diabetes, heart disease, obesity and an increased risk for depression. This is most likely due to the fact that exposure to light suppresses the secretion of melatonin and lower melatonin levels are association with these types of health problems.
- Children are most at risk for the adverse effects of blue lights. Before age 10, children’s eyes are not fully developed. The crystalline lens and cornea are still largely transparent and overexposed to light Like UV radiation, most blue light exposure occurs before kids are 18 years old. Parents should limit the amount of screen time their children are permitted.
Blue Light Suppressing Technology That Helps Regulate Circadian Rhythm
Blue light technology can control the spectrum of light emitted to help provide the right type of light at the right time of day. Here are some ways the technology has advanced to help regulate circadian rhythm:
- Blue light filtering apps are available and often free. These apps turn on when the clock on your phone shows that the sun has set and place a red overlay on the screen which counteracts the blue light effects.
Amazon has a feature known as ‘Blue Shade’ on its Kindle Fire tablets which limits the amount of blue light that reaches your eyes. The feature can be turned on or off with one tap, and also lets you adjust the filter’s color settings and brightness.
- LED pre-sleep lights emit very little blue light, encouraging the body to release melatonin, the hormone that tells the brain that it is nighttime
- In 2016, Apple introduced ‘night mode’ for iOS devices designed to help owners sleep. The ‘night shift’ mode was unveiled as part of a beta version of iOS 9.3, the firm’s next update. In the morning, it returns the display to its regular settings.
- LED lights can be specifically engineered to help regulate a healthy circadian rhythm. Some are designed to filter out blue light wavelengths, promoting better sleep patterns, which can strengthen the immune system. Others emit increased blue wavelength light, promoting greater energy and attentiveness. These light bulbs use the same principles NASA used on the International Space Station to improve the sleep and performance of astronauts by mimicking a normal day/night cycle. It’s all about using the right light at the right time.
Tips to Keep Your Circadian Rhythm Balanced
- Get outdoors each day to get natural blue light. Exposure to blue light during daytime hours can help maintain a regular circadian rhythm.
- Avoid looking at bright screens beginning two to three hours before bed. Too much blue light at night can disrupt circadian rhythm cycle, potentially leading to sleep problems and daytime fatigue.
- If you are going to look at a device before trying to sleep, turn on the reading or evening mode. At the very least, turn down the brightness on your device and increase text size.
- If you work a night shift or use a lot of electronic devices at night, consider wearing blue-blocking glasses or installing an app that filters the blue/green wavelength at night.
- Invest in a pair of blue light blocking glasses.
- Use dim red lights for night lights.
- Consider changing light bulbs in lighting that you often use prior to bed to bulbs that are colored yellow, orange or red.
- Salt lamps give off the perfect red-orange glow and is another great option.
- Pre-sleep LEDs promote sleepiness and calmness as shown in the diagram below.
The Light Wavelength Spectrum
High blue level lights promote alertness while low blue level lights support sleep.
Everyone needs to take precautions against the effects of blue light. You can help yourself sleep well by turning off electronic devices a couple of hours before heading to bed. Using blue light filtering apps and/or computer glasses at night can also greatly reduce negative effects associated with using blue light devices. Use the right light for the right task. Switch out bedroom lights to a more sleep inducing light such as pre-sleep LEDs to help give yourself a night of good sleep. We all want to sleep well, so making the effort to do so is well worth it!
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