Staying up to catch your favourite TV show or using your iPad before bed could make you depressed, experts warn.
New research has connected back-lit devices such as tablets to an increase in the stress hormone cortisol, as the light they give out appears to cause chemical changes in the brain.
Though this research is only on mice, it backs up previous studies that have found using back-lit screens at night interrupts natural sleeping patterns. And as we all know, getting enough sleep is vital not only for keeping our body healthy and alert, but also for fighting depression and keeping our mind in good health too.
[Related: The real reason you're tired all the time]
Study leader Samer Hattar, professor of biology at Johns Hopkins University in the US, explained that the levels of light they tested were similar to what people experience in their own living rooms in the evening, or for nightshift workers in the workplace. And the findings showed how influential light is on our bodies and mood.
“Basically, what we found is that chronic exposure to bright light elevates levels of a certain stress hormone in the body, which results in depression and lowers cognitive function,” Hattar said.
The team found that as well as raising cortisol levels, bright lights also affected cells in the mice’s eyes, which influence the area of the brain that controls mood, memory and learning.
A spokesman for John Hopkins said: "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.”
A better option before bed would be to put your iPad and smartphone to bed eary and pick up a book (or a specially designed e-reader), have sex or convince your partner to give you a massage.
Do you have a healthier bedtime routine? Share it with us on Twitter.