Lying in bed late at night glued to Facebook and Youtube, texting friends on your smartphone, or watching TV, could be raising your risk of depression.
American scientists used mice to test how exposure to bright lights during sleeping hours affects behaviour and stress levels.
They found that mice regularly exposed to light at night showed symptoms of being depressed. They showed less interest in doing fun things in their cages, became less likely to investigate new objects and stopped moving around so much.
These mice were also found to have higher levels of cortisol, the stress hormone.
Cortisol is thought to result in lower cognitive function and depression.
The scientists also found that exposure to bright lights affected parts of the mice’s eyes, a type of cell thought to impact the part of the brain responsible for learning, memory and mood. This part of the eye is known as the ‘intrinsically photosensitive retinal ganglion cells’.
Samer Hattar, professor of biology at Johns Hopkins University in the U.S. said even lights usually found in living-rooms, or at the work-place at night could elevate cortisol levels – bad news for shift workers and technology-addicts.
Prof Hattar explained that although the study was carried out on mice, the results are applicable to humans because we share many similarities with rodents.
“I’m not saying we have to sit in complete darkness at night, but I do recommend that we should switch on fewer lamps, and stick to less-intense light bulbs: Basically, only use what you need to see,” he said.
Using technology late at night also restricts sleeping time, which can contribute to tiredness, irritability and lower concentration levels the following day.
Counselling can help people suffering from depression. To find out more about symptoms, diagnosis and treatment, please visit our Depression page.
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