Your eyes are not only for useful for seeing, as they also send signals to your brain to you help regulate your circadian rhythm (awake-sleep cycle). At least in the natural world—before the invention of computer screens and televisions—at night your brain would receive less light, and that darkness stimulates the release of the hormone melatonin. Melatonin tells your brain “go to sleep”.
Now that many people are using computers before bedtime, and even taking tablet computers to use in bed before sleep, scientists have been conducting research to see if this might cause sleep disturbances. There is particular concern about the light coming from the most modern screens, for example from the iPad, that use LED (light-emitting-diode) sources, because these devices emit a light that contains much more blue than natural light.
Scientists at the Lighting Research Center, Rensselaer Polytechnic Institute (Troy, New York) had thirteen experimental subjects use a computer tablet at night—playing games, reading, and watching movies. They found that after two hours of exposure like this, their melatonin levels decreased by 22 percent.
Another similar study last year from the University of Basel (Switzerland) showed that in volunteers exposed to blue light, melatonin levels remained low all night.
Researchers into human circadian rhythm are concerned that there could be other negative effects on our bodies beyond sleep disturbances when our natural awake-sleep cycles are disrupted. As we reported in Mais Saúde several months ago, women who work night shifts have been shown to have up to a 30% increased risk of breast cancer.
On the flip side, we can also be smart and use to advantage how different light colors may affect our organisms. A small study done earlier this year on a group of elderly people showed that just an extra 30 minutes exposure to blue light daily for four weeks significantly improved their cognitive abilities. Who knows, maybe the same technique might be useful in other cirumstances, for example in the weeks before a vestibular or concurso?
Innovators in lighting are joining forces with circadian rhythm scientists and are working on new types of light sources that can change wavelength and color throughout the day, as our internal needs change from wakefulness to sleep.
In the meantime, the useful information you can take from today’s post is: if you have problems sleeping, you might try avoiding using a computer or tablet or iPhone screen for a couple hours before bedtime. Or at least minimize their use, and use them on lower brightness.
The interaction between light and colors and our bodies is fascinating and complex, and we will keep you updated here in Mais Saúde!
If you would like to find a doctor in Brazil, you can do so through our main website: www.procuramed.com.
See also in ProcuraMed:
Esta postagem também está disponível em: Portuguese (Brazil)