Nighttime exposure to artificial light disrupts the body’s circadian rhythm, which has been associated with cancer, diabetes, depression and heart disease. Recent research indicates that melatonin-suppressing blue wavelength light is especially harmful. Blue light is emitted not only by electronic devices, but also energy-efficient light bulbs and other common light sources.
In the ongoing quest to improve sleep, researchers are experimenting successfully with a variety of blue-light filters. During cataract surgery, instead of removing the eye’s damaged lens and inserting a regular artificial lens, scientists at China’s Sichuan University implanted blue light-blocking lenses in patients. After two months, test subjects—26 women and 14 men, with an average age of 74—experienced the following:
- More sleep at night.
- Improved sleep quality.
- Diminished levels of daytime dysfunction due to sleepiness.
- Number of “poor sleepers” decreased.
Another study of 20 adults who wore blue-light blocking glasses for three hours before sleep showed that sleep quality and mood improved, compared with the other participants in the study, who wore ultraviolet-light blocking glasses. And in a study of nightshift workers who wore blue-light blocking glasses at or near the end of their overnight shifts for four weeks, scientists at Quebec’s Universite Laval found that workers’ overall sleep amounts and quality increased.
While nighttime exposure to blue wavelength light is damaging, daytime exposure to blue light has a positive effect on the body. A study of 94 office workers found that daytime exposure to blue light during work hours resulted in improvement to daytime alertness, mood and concentration, decreased daytime sleepiness and better sleep at night.
If you don’t have special goggles or need cataract surgery, here are some low-tech suggestions to help improve sleep:
- Limit exposure to artificial light, including computer screens and televisions, one to two hours before bed. Reading under moderate lamplight is fine, but make the last 60 minutes of your bedtime ritual electronics-free—and keep electronic gadgets and devices out of the bedroom altogether.
- Get light exposure during the day. Both sunlight and artificial light can help strengthen circadian rhythms and boost daytime alertness, leaving you better prepared to sleep at night.
- If you need access to light in the middle of the night, use small nightlights. Bright hallway or bathroom lights flood your system with melatonin-suppressing light that will prevent you from getting back to sleep.