Staying on your phone or computers late at night may be making you dumber and depressed, according to researchers at John Hopkins University.These changes in mood are caused by special non-visual light-sensing cells in your eyes, which don’t form pictures in your brain but are sensitive to blue lights — like that from your smartphone or computer. Activating these cells can mess with your brain, causing depression and difficulty with learning and memory.
Artificial light has changed our sleeping patterns and researchers thought that negative affects stemming from this were due to sleep deprivation. The research, published Wednesday, Nov 14, in the journal Nature, set out to see what truly causes these changes in mice and how they would react if instead of having a 24 hour day with 12 hours of light and 12 of darkness, they had a 7 hour day with 3.5 hours of light and 3.5 hours of darkness.
Depression was determined by observing preferences for sugar how they did on a swim test — depressed mice take in less sugar and are slower on the swim test. They also had higher levels of a hormone associated with depression. Intelligence was determined by showing the mice old toys in a new environment if the mouse recognises the toy as something it’s seen before, their memory and learning is working correctly
The researchers found that normal mice exposed to these seven hour days continued regular sleeping patterns, but still showed behavioural signs of depression and learning difficulties.
When the researchers studied mice that didn’t have these special light-sensing eye cells, they didn’t see these same changes in their mood and learning abilities.
Because their sleep wasn’t impacted, the researchers said the negative effects weren’t likely to be caused by sleep deprivation, or by a messed up circadian rhythm or “biological clock,” which controls sleep and metabolism at different times of the day. They think that the blue light activates these non-image producing cells, which stimulate the brain’s limbic system, the centre of emotion, memory, and learning.
“I feel like your grandmother because this is very simple advice. We think that you should be exposed to bright light and go outside in the day and avoid very bright light or more blue shifted white lights at night,” study researcher Samer Hattar said in a YouTube video by Johns Hopkins.
He also suggested reading by a light bulb at night, instead of using a tablet or computer.
See the Johns Hopkins video below:
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