We all sleep in different conditions. Someone prefers to sleep with a night light, getting used to such lighting from childhood, someone prefers complete darkness in the room, and someone can even sleep with the lights on. As it turns out, even a small amount of light in your bedroom can seriously increase your risk of depression. This conclusion was reached by the Japanese scientists Kenji Obayashi, Keigo Saeki and Norio Kurumatani. They published the results of their research in The American Journal of Epidemiology.
The reason for this phenomenon is not completely clear, but scientists believe that all this is due to a person's 24-hour circadian rhythm, which tells him when to sleep and when to wake up. This rhythm is programmed in us by environmental factors. In the case of humans and animals, light directly affects the production of the hormone melatonin in their bodies, which regulates circadian rhythms. In other words, we want to sleep when the sun goes down and wake up when it comes up. But not everything is so simple if there are hundreds of sources of artificial light around us, including LEDs on devices, light from headlights of cars passing outside the window, screens of smartphones, smart watches and tablets, computer monitors, night lights, and so on.
Night light sources, or LAN (Light At Night), as Japanese scientists have designated them in their research, seriously distort our natural sleep-wake cycle. The studies involved over 860 older adults without any signs of depression. For four years, some of the participants in the experiment slept in rooms with artificial lighting, and the other part - in completely dark bedrooms. The researchers found that those who slept in a room with a light level of 5 lux or higher showed a significantly higher risk of depression than those who got completely dark sleeping rooms. As a result, 73 participants in the experiment showed signs of depression already after 24 months.
Of course, Japanese scientists admit that for the completeness of the experiment, similar research should be carried out on young people. After all, the elderly may react somewhat differently to lighting. But be that as it may, it is highly likely that even young people will react to sleep in the light in a similar way. In the meantime, scientists recommend that we avoid sleeping in the same room with artificial light sources and, if possible, curtain the windows into the room with thick curtains that do not let light from outside. They also remind us that the radiation from the displays of modern gadgets (especially cold blue light) can also negatively affect the quality of our sleep.
Sergey Gray