Many people have erratic and disturbed sleep patterns these days. Getting to bed very late at night only to watch TV or browsing the internet, waking up often during the night or simply being unable to fall asleep for very long time seem to be the typical problems of many office workers.
Physical laborers are less affected by these aliments, and you might wonder why. Well, research suggests that this can directly correlate with the use of bright computer screens until late in the evening.
Just two hours of working with an iPad at maximum brightness significantly disrupts melatonin secretion, the research found.
What is melatonin? Where it is produced in the brain? How does it work?
Melatonin is a simple organic compound which plays an important role in the body. It is produced by the pineal gland located in the center of the brain. Melatonin production is inhibited by light and stimulated by darkness. Due to this correlation, melatonin is sometimes aptly called the “darkness hormone”. Obviously, due to the location of this gland in the center of brain, light cannot reach there.
Photosensitive cells of the eye retina send the signals regarding the level of light to the pineal gland via several neuronal connections in the central nervous system and spinal cord. One of the important connecting points is the suprachiasmatic nucleus (SCN), the "master clock" of our circadian rhythm.
The circadian rhythm is the body’s sleep and wake cycle. The SCN sets the body clock, and melatonin plays the role of an adjusting or tuning mechanism. Melatonin helps to “reset” the clock, for example when we cross several time zones when traveling. Jet lag experienced by travelers is directly connected to the readjustment of circadian clocks with the help of melatonin. Melatonin synchronizes circadian cycle with the real cycle of day and night experienced by the body.
The circadian cycle can be “fooled”
Due to the connection between melatonin production and light exposure, the circadian cycle can effectively be “fooled” by provoking excessive exposure to artificial light. This is exactly what happens if we use light emitting devices like laptop computers and tablets in the evening. Exposure to light at this time of the day leads to a significant decrease in melatonin levels, sending a wake-up signal to the SCN.
Other scientific research has shown that the production of melatonin is affected not simply by light in general but by the short wave blue light (with a wavelength of approximately 470 nm). This is the bluish-white type of light generated by the screens of many of our computer devices.
Circadian Cycle, Its Disruption And Negative Effects On Health
Negative and positive effects of melatonin suppression
Disruption of sleep is the most obvious effect of melatonin suppression through a chronic excessive exposure to the intensive blue light of the computer screens we're now all glued to so much of the time.
A surprising connection between breast cancer and working the night shift was recently found. Women who regularly work during the nights (such as hospital nurses or firefighters) have a higher risk of developing this disease. Regular night shifts inhibit the normal production of melatonin.
Everything mentioned above does not mean that bright computer screens are dangerous to our health. On the positive side, it should be mentioned that early morning exposure to the light emitted by computer screens may have its advantages. Apart from having a waking up effect, light exposure of this kind can be used as a light therapy for people who suffer from seasonal affective disorder. Many people suffer from higher depression levels and not a particularly bright mood during the winter when the daylight is limited by just few hours. Working with bright screens can provide this additional crucial exposure to the light, which helps to improve general mood.
Changes of lifestyle can help to avoid the suppression of melatonin production in the evening
Like many other modern innovations, bright computer screens should be used with a clear understanding of their effect on our health and well-being. Our busy lifestyle these days, however, adds to the pressure on our health. Many people simply can’t afford not to work in the evenings, whatever the consequences may be. Turning off your computers in the evening just to gain access to a good night's sleep is not an option for many modern workers. What can be done in these circumstances?
- Certain changes to your style of work could help.
- Printing out the documents and reading them on paper rather than on computer screens significantly reduces the light exposure.
- Reducing the brightness of screens also helps.
- It is also possible to change the color of background while reading some types of documents. For example, text with white letters on black background certainly reduces the light exposure.
- It may take a bit of time to get used to these changes, but the benefits are obvious.
- Some tablet manufacturers are considering now the production of smarter devices which would regulate the light exposure depending on the time of day.
Still, it is better just to give some rest to your eyes in the evening or resort to the old-fashioned but very eyes friendly paper books.
- Arendt J. (2006) Melatonin and human rhythms. Chronobiol Int. 23(1-2): 21-37
- Figueiro, M.G., Wood, B., Plitnick, B. et al. (2011) The impact of light from computer monitors on melatonin levels in college students. Neuro Endocrinol Lett. 32(2):158-63
- Glickman G, Levin R, Brainard GC. (2002) Ocular input for human melatonin regulation: relevance to breast cancer. Neuro Endocrinol Lett. 23 (Suppl 2): 17-22
- Skene DJ, Arendt J. (2006) Human circadian rhythms: physiological and therapeutic relevance of light and melatonin. Ann Clin Biochem. 43(Pt 5): 344-53
- Wright HR, Lack LC, Kennaway DJ. (2004) Differential effects of light wavelength in phase advancing the melatonin rhythm. J Pineal Res. 36(2): 140-4
- Photo courtesy of 83905817@N08 on Flickr: www.flickr.com/photos/83905817@N08/7676645672