Using iPad at night 'could trigger depression'
Using your iPad or watching television late at night could make you depressed, according to a study that shows exposure to bright light during sleeping hours affects behaviour and stress levels.
According to a recent study using your iPad or watching television late at night could make you depressed Photo: ALAMY
American scientists found that mice regularly exposed to light at night became
‘depressed’ - showing less interest in doing ‘fun’ things, being less likely
to explore new objects in their cages and not moving around as much. They
also had higher levels of cortisol, the stress hormone.
Samer Hattar, professor of biology at Johns Hopkins University in the US,
said: “Basically, what we found is that chronic exposure to bright light -
even the kind of light you experience in your own living room at home or in
the workplace at night if you are a shift worker - elevates levels of a
certain stress hormone in the body, which results in depression and lowers
cognitive function.”
He and his colleagues also found that the bright light affected special cells
in the mice’s eyes, called intrinsically photosensitive retinal ganglion
cells, which affect the part of the brain that manages mood, memory and
learning.
Although the study was in mice, Prof Hattar said mice and men were similar in
certain ways and so the study held lessons for people.
“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.
A spokesman for Johns Hopkins: "When people routinely burn the midnight oil,
they risk suffering depression and learning issues, and not only because of
lack of sleep. The culprit could also be exposure to bright light at night
from lamps, computers and even iPads.
The study is published in the journal Nature.
The study is published in the journal Nature.
