It is not uncommon for most of us to go to bed while watching a movie, surfing social media sites or just streaming YouTube on our cell phones. Looks like it is not good news for people who are a slave to this habit. Recent research has uncovered how light-sensitive cells in the eye can reset the internal clock and disturb our sleep patterns when exposed to light from the screen.
The findings of the study that have been published in the journal Cell Reports might help in improving the treatment of insomnia, jet lag, migraines, and circadian rhythm disorders.
In case you are wondering what circadian rhythm is, our body has an internal clock that is typically synced with a 24-hour day-and-night pattern, also known as sleep-wake cycle. It helps in guiding our sleep-wake timings, eating habits and regular day-to-day activities by obeying signals from an area of the brain that monitors ambient light.
“Because we use artificial sources of light, our sleep-wake cycles are no longer tied to patterns of day and night”, the study states. “This lifestyle,” says senior study author Prof Satchidananda Panda, “causes disruptions to our circadian rhythms and has deleterious consequences on health”, according to a report in Medical News.
How do screens disrupt our circadian rhythm?
“The backs of our eyes contain a sensory membrane called the retina, whose innermost layer contains a tiny subpopulation of light-sensitive cells that operate like pixels in a digital camera. When these cells are exposed to ongoing light, a protein called melanopsin continually regenerates within them, signaling levels of ambient light directly to the brain to regulate consciousness, sleep, and alertness”, Science Daily stated.
Melanopsin plays an important role in synchronizing our internal clock after about ten minutes of illumination and, under bright light, it generally suppresses the hormone melatonin, a sleep-regulating hormone.
“Compared to other light-sensing cells in the eye, melanopsin cells respond as long as the light lasts, or even a few seconds longer,” says Ludovic Mure, staff scientist and first author of the paper. “That’s critical because our circadian clocks are designed to respond only to prolonged illumination.”
The researchers plan to further their research and find ways to influence melanopsin to reset the internal clocks and help with insomnia.