The perils of excessive blue light from our increasingly omnipresent “goodbye nature and hello high tech, I can’t let go of my mobile,” way of living, are making their mark in multiple ways. Of note, the latest research which indicates that, “repeatedly exposing lab mice to blue light at night can lead to developing symptoms of depression,” has just been reported in the reputed journal, Nature Neuroscience, along with a report on what this could mean for us.
In the past, studies indicated that when compared to employees who work in the daytime, those on the night shift, are more prone to depression. The reason/s behind it, still remain somewhat blurred. However, more recent research has determined that individuals who regularly use a smartphone at night, may well be contributing to their depression. Taking this as a starting point, the scientists questioned whether experiencing light in the eyes at nighttime, could contribute to the issue; and if this is the case, whether it could just concern blue light.
Putting the Spotlight on Blue Light
Although our prime source of blue light exposure comes from being outside in the sunlight, there are also various man-made indoor sources, such as: flat screen TVs, and LED and fluorescent lighting. However, smartphones, electronic notebooks, computer screens, and other digital devices, top of the list, when it comes to emitting significant amounts of blue light. And while the: “amount of HEV light these devices emit, is only a fraction of that emitted by the sun, the time people spend using them, and the proximity of these screens to the user’s face, have many health care professionals concerned about possible long-term effects of blue light.
Slacking For a Sugar Reward
Going back to the study research: in order to see if there was any discernable affect on their behavior, the scientists subjected the laboratory mice to blue light every night over a period of three weeks (for two hours per night). In the beginning, there were no visible signs of change, however, three weeks into the project the mice began to work less hard for a sugar reward and tried less hard to escape when presented with the possibility; both considered to be signs of depression in mice. Moreover, even after the night light exposure was discontinued, the depressive symptoms carried on for up to 21 days.
Why at Night?
The scientists also looked at the animals’ brains. In doing so, they determined that there is a specific kind of light receptor in the mouse retina that leads to brain areas associated with mood. Once these were disconnected, the mice did not become depressive due to exposure to blue light at night. [Furthermore], the pathways became much more active when processing blue light at night versus daytime. Clearly, the latter explains why this depressive surge is only linked to nighttime.
Follow the National Sleep Foundation’s advice, and turn off your mobiles, screens and WI-FI, at least half an hour before going to bed. As Hemmingway said: “The sun also rises..”