The Scoop on Blue Light
You shut your lights off around the house as bedtime approaches, however, the light from your smartphone, tablet and computer often stay on. It is one of the lights emitting from your electronic device, which is a blue light, that causes a problem. If you have trouble sleeping and are a frequent user of electronics, listen up. A Harvard study found that blue light, the wavelength common in smartphones and tablets, disrupts the internal body clock, hindering sleep.
The Science Behind It
Our bodies are kept in sync with the rhythm of the day and night by our internal body clock. The body clock, called the circadian rhythm, uses light to tell time and all different types of light affect the body differently. During the night, light throws the circadian rhythm out of whack, causing sleep to suffer. Although blue wavelengths are beneficial during the day, increasing attention and mood, they have been found to be the most harmful and disruptive at night.
An overwhelming amount of studies found that working the night shift, meaning exposure to light at night, was linked to diabetes, obesity and heart disease. Exposure to light decreases the secretion of melatonin, a hormone that influences circadian rhythms. The Harvard study linked blue light to diabetes and obesity. The researchers put 10 people on a schedule that gradually changed the time of their circadian rhythms. Their blood sugar levels were found to have increased, putting them in a pre-diabetic state. Their levels of leptin, a hormone that makes you feel full after a meal, also went down. Even dim light was found to have an impact on our circadian rhythms. Stephen Lockley, a Harvard sleep researcher, says that just eight “lux,” a level of brightness exceeded by most table lamps, has a powerful effect. Light at night is a main reason people don’t get enough sleep, Lockley says, and researchers have linked limited sleep to increased risks for depression and diabetes.
Blue Light Potency
Although any light can decrease melatonin, blue light is significantly more powerful. The Harvard study compared the effects of 6.5 hours of blue light exposure to a comparable brightness found in green light. The discovery? Blue light decreased melatonin for about twice as long as the green light, shifting circadian rhythms by twice as much. A study by the University of Toronto compared the melatonin levels of those exposed to bright indoor light wearing blue light blocking goggles to people exposed to regular dim light without goggles. They found that the levels of melatonin were about the same, proving that blue light is a strong suppressor of melatonin.
What To Do
So how can you combat this powerful blue light and get back your much-needed full night of sleep?
• Avoid looking at bright screens about two to three hours before bedtime.
• Expose yourself to lots of blue light during the day. This will boost your ability to sleep at night, and heightens your alertness and mood at daytime.
• Use dim red lights for night lights, as red light has the least effect on your circadian rhythm.
• If you’re a night owl or work a night shift, considering purchasing a pair of blue-blocking glasses.
• Turn off your electronic device and allow yourself a good night’s sleep!