Light pollution interferes with sleep patterns, a new study found. If you find it hard to sleep at night, the street lamps and other light sources in your neighborhood might be the problem.
Study author Dr. Maurice Ohayon said that "our world had become a 24/7 society." The use of outdoor lighting such as street lamps not only increases security and safety in neighborhoods but also allows night activities to become more dynamic.
However, the constant presence of lighting means we are seldom exposed to darkness. The reduced exposure to darkness may be affecting our sleep, said Ohayon from California's Stanford University.
Ohayon conducted an eight-year phone survey on 15,863 participants. The people were asked about their quality of sleep, psychiatric and medical conditions as well as sleeping habits. The study focused on the quantity of outdoor light the participants were exposed to during the night.
Outdoor nighttime lights in urban areas with approximately 500,000 residents or more are about three to six times stronger than the light sources in rural areas or small towns.
The study found that outdoor lighting affects the participants' sleep duration. Moreover, it is also linked to sleep disturbances.
Participants in urban areas with strong outdoor lighting were 6 percent more likely to have less than six hours of sleep per night compared to people in areas with less intense nighttime lights.
Urban dwellers were also more likely to suffer from poor sleep quality and quantity compared to people living in areas with less harsh nighttime lighting. About 29 percent of the urban dwellers are not satisfied with the quality or quantity of their sleep compared to the other 16 percent.
Participants who were exposed to more nighttime light have higher chances of reporting fatigue compared to the other group, 9 percent versus 7 percent, respectively. On average, the former also slept less per night (402 minutes) compared to the latter (412 minutes).
People exposed to harsher light sources have higher chances of waking up confused in the middle of the night (19 percent) compared to people exposed to less light (13 percent). The former were also more likely to suffer from impaired functioning and extreme drowsiness, 6 percent versus 2 percent.
"Light pollution can be found in any sizable city in the world. Yet, excessive exposure to light at night may affect how we function during the day and increase the risks of excessive sleepiness," added Ohayon.
Photo: Elias Quezada | Flickr