For many people across the country, it can be next to impossible to turn off their phones at night and get the rest they need. It's estimated that the average Briton spends up to 10 hours per day staring at screens, with 3 of those hours looking at a phone screen. Whether browsing through your Facebook feed, checking your email one last time before getting to sleep, or aimlessly binging YouTube videos, smartphones offer an endless array of distractions that can prevent us from getting to sleep at a decent hour.
Recent studies have shown, however, that there might be another way in which our smartphones are keeping us from getting a restful night of sleep. In this brief article, we delve into the impact of the blue light emitted by most smartphones on our sleep patterns and provide some suggestions for mitigating this common yet potentially hazardous health issue.
The Problems with Blue Light
Light makes up a small portion of the electromagnetic spectrum—the spectrum that breaks down the various kinds of radio waves and groups them by their frequency. Longer frequencies, such as infrared and radio waves, can be easily blocked and don't penetrate the skin. Shorter wavelengths, however, such as ultraviolet (UV) radiation, x-rays, and gamma rays, can pass through tissue and cause damage.
As you approach shorter wavelengths, the risk of eye damage increases. Blue light, also known as high-energy visible (HEV) light, covers the wavelengths of 380 to 500 nanometres. As the wavelength shortens, the risk of eye damage increases.
Blue light, with wavelengths between 450 nanometres and 500 nanometres, influences sleep quality and mood. Wavelengths below 450 nanometers are associated with age-related macular degeneration (AMD).
Below wavelengths of 380 nanometres (such as ultraviolet light), the risk of cataracts increases.
Smartphones are designed so that we can see what's on the screen even when outside during a sunny afternoon. To achieve this, they emit various wavelengths of light simultaneously. Most screens are composed of small light-emitting diodes (LEDs) that can be lit up in red, green, or blue. Using these primary colours, they can create almost every colour we can see. When all three colours are emitted at once, they create white light - this is known as additive colour.
This means that even when your phone appears to be emitting white light, it is, in fact, emitting red, green, and, most importantly, blue light simultaneously. Even when the screen is black, the backlight of LCD and LED screens remains lit, which is why they appear dark grey rather than truly black. Modern OLED and plasma displays do not emit light when they are displaying black. Studies have shown that OLED technology is less strenuous on the eyes, as the devices that emit light can be switched off rather than dimmed.
To make matters worse, many electronic device interfaces are blue and white, further contributing to eye strain. Think about the most common applications you use - there's a good chance the icon and interface are accented in blue.
Blue light influences our circadian rhythm, which controls our natural sleep and wake cycle. The shorter wavelength of blue light is able to penetrate the thin skin of the eyelids. Closing our eyelids does not stop our eyes from functioning; hence, you can see changes in light when your eyes are closed.
In terms of general eyesight, long-term exposure to strong blue light (such as that emanating from your smartphone) can increase the probability of macular degeneration. Blue light can penetrate the innermost layers of the retina at the back of the eye, potentially damaging the light-sensitive cells located there. Furthermore, high-energy blue light scatters much more easily than lights of longer wavelengths, and this is what leads to the eye strain that is so common with computer users.
Moreover, the blue light radiating from our smartphones at night can also confuse our brains. Because this light mimics the natural light of the sun, prolonged exposure to our smartphones at night can disrupt our circadian rhythm, our natural body clock. Long-term disruption of our internal body clocks has been linked to various other health conditions, including obesity, increased risk of heart attacks and diabetes.
Finally, and perhaps more seriously, exposure to the blue light of our smartphones during nighttime hours can also cause our brains to stop producing melatonin. Melatonin is a hormone produced by the pineal gland of the brain that, among other functions, lets your body know when it is time to go to sleep. Without this hormone, it becomes increasingly difficult for our bodies to determine when we need to rest.
What Can We Do?
Concerns about exposure to blue light from cell phones are real and need to be taken seriously. However, that doesn't mean that we have to simply give up our smartphones.
For people who are disciplined, simply turning off and storing away their smartphone 2 to 3 hours before bedtime should be more than enough to limit the negative effects of blue light. If you go to bed at 10 pm, make it a habit to turn off your phone at around 7 pm, and spend more time with your family or reading a good book.
If you feel that you simply cannot do without your smartphone during the evening or night-time, consider installing a blue light filtering app. This will help to avoid difficulties falling asleep by adapting the screen on your phone to the specific time of day. The filter automatically changes based on the sun cycle and your local sunset and sunrise times. When activated, your phone screen will shift to a shade of red or orange. This reduces the effect of blue light.
While we may all spend a bit more time away from the screens that dominate our lives, fortunately, there are ways we can still enjoy the benefits of technology (even during nighttime hours) without compromising our sleep and health.
If you are struggling to sleep, there are over-the-counter treatments, such as Nytol, that can help alleviate short-term insomnia. It is important to speak to your doctor or a pharmacist before taking medicines for insomnia, especially if you are taking other medicines.
