The human eyes are not adapted well for seeing in the dark. Unlike owls or cats, people need help in order to see in dim or dark lighting conditions. Because of this, humans have designed homes and cities that are brightly lit on a 24/7 basis. This is good except for when you’re trying to sleep. Too much light in your sleep environment is associated with weight gain, obesity, sleep disorders, depression, cancer and other serious health conditions. Consider the types of light pollution, the ways in which light pollution could be impacting your sleep and what you can do about it.
Disability Glare
Disability glare is a result of a single, intensely bright light in an otherwise dark environment. For example, a single street light on a road. The glare of the light makes you look elsewhere because the retina cannot handle the brightness. The result is that everything else looks dark except the lone source of light.
Exaggerated Darkness
Exaggerated darkness is a concept in which the positioning of a bright light in front of your eyes makes it nearly impossible to see what is behind the light. For example, when you’re driving at night, extremely bright LED head lamps on another vehicle can temporarily blind you and prevent you from seeing what is behind that vehicle. A bright light could make it difficult for you to see what is lurking in a dark alley. Properly shielded lights direct the brightness away from your face so that you can see a larger area.
Impacts on Sleep
Exposure to bright lights in the evening disrupts your body’s circadian rhythm. This is your internal clock that triggers metabolic and hormone changes that prepare your body for sleep. Of all the lights in the visible spectrum, blue light is the type most strongly associated with sleep disruption. The bright lights reduce your body’s ability to make and release melatonin, which is a hormone that makes you feel sleepy and helps you fall asleep and stay asleep. Disruption of the circadian rhythm also lowers the production and availability of serotonin. Serotonin is a neurotransmitter in the brain, and low levels of it are associated with depression and mood disorders.
Effects of Circadian Rhythm Disruption
Scientists are only beginning to discover the wide range of effects on circadian rhythm disruption. They believe that disrupted sleep is associated with mood changes, cravings for carbohydrates, impaired immune system function and slower healing times after an injury. Research also indicates that disrupted circadian rhythms increase your risk of cancer, diabetes and heart disease. People with chronic sleep disruption face high rates of depression and suicidal ideation.
What You Can Do About Light Pollution
In addition to lobbying your local government about ways to curb light pollution, there are a few things that you can do in order to darken the environment in which you sleep. Maintain a consistent sleep routine. Consider purchasing room-darkening blinds and drapes. These block out a high percentage of outdoor light. Eliminate electronics from your bedroom. Even a small LED light from a charger could be enough to disrupt your sleep. Charge your devices somewhere else, such as the kitchen or living room. Consider a sleep mask if you’re able to tolerate it on your face.