In the journal “Journal of Applied Physiology”, sleep scientists of the “Universitaere Psychiatrische Kliniken Basel, Switzerland” and scientists of the “Fraunhofer-Institut fuer Arbeitswirtschaft und Organisation Stuttgart, Germany” get to the point: the one who sits in the evening in front of an LED-screen delays the sleep-wake-cycle but clearly is mentally fitter. In their investigation all tested persons in front of an LED-screen clearly reacted faster, felt more awake and clearly performed better during a cognitive test.
More and more people are spending their time with watching TV or in front of computer screens that are furnished with the so-called LED (Light Emitting Diodes)-backlight. With about 464 nanometers wavelength they are emitting increased blue light. And this is exactly what our eyes are reacting very sensitively to.
LED-Frequencies are influencing our melatonin-Level
The study has made it clear: the LED-light is also influencing our hormone level and thus our sleep-wake-cycle, too. Light with this wavelength is especially influencing the level of the important sleeping hormone melatonin. Because of the delayed release or a temporary blockade the cognitive performance during night gets especially improved.
Reaction time and concentration improve
During experiment, male test persons from the age of 19 to 35 years spent five hours in front of LED-screens during the evening. Compared to the ones in front of computer screens with conventional lighting their reaction time was about 20 per cent faster. Subjectively and objectively they were more awake and showed better results in a word-pair-learn-test.
Furthermore, the sleeping hormone melatonin was suppressed longer. Out of this reason, the biologically clocked phase of tiredness starts later and falling asleep gets harder. Picture quality and visual comfort both were rated the same, screens without LED-technology rather got classified brighter.
People who have to work a long time in front of a sceen might choose LED out of this reason. But, if you want to go to bed early and have to get up early you rather will have problems to fall asleep easily.
Out of this reason, the scientists suggest to produce computer screens where the wavelength individually can be programmed so that in the evening the sleep-wake-rhythm doesn’t get disturbed. (source: Journal of Applied Physiology, 2011; doi: 10.1152/japplphysiol.00165.2011, Universität Basel, 03.25.2011 – NPO)
Melatonin – important for sleep-wake-cycle and healthy sleep
Who already has observed this phenomenon with himself knows that possibly a screen which is reducing the release of the human sleeping hormone melatonin might be responsible for that. The consequences reach from bad, disturbed sleep to noticeable daytime sleepiness and out of this reason even might be responsible for serious health disturbances.
Melatonin is produced in our pineal gland in the brain and significantly determines our day-night-rhythm, meaning our inner biological clock. Specificity: The hormone gets released by the influence of darkness so the release of melatonin increases ten times during nighttime.
But, in case it is too bright during night – a problem especially shift workers and people who have to work late know and suffer under – the body is releasing a lot fewer melatonin. Since the hormone is also needed for cell reproduction this can lead to sleep disturbances and serious health damages like cancer.
The chronical lack of melatonin may lead to an impairment of the chronobiological stability and by that to the impairment of the so important wake-sleep-dream-rhythm. Consequence: a weakening of the immune system with the danger that the defensive forces of the body significantly get diminished.
Blue-Light influences production of melatonin the most
The blue-light of the computer screen seems to be especially “tricky”. Because, like neuro-scientists of the Jefferson Medial College were able to prove in an investigation in 2001, the wavelength of blue light (446-447 nanometer) has the strongest influence on the melatonin level in blood.
The possible consequences of that are shown in a Japanese study where especially many people are working in front of a computer screen until late. According to that, 53.7 % of all internet-users go to bed late, 45.4 % of them are having sleep debts (too less sleep) as well as delayed phases of falling asleep and additionally often sleep-through-disturbances.
This is one more evidence that besides the biologically necessary “hardware” – the proper sleeping underlay (bed) – healthy sleep also needs the “software” meaning the rules of sleep hygienic, too. And disturbing influences of light, noise or electromagnetic pollution belong to that.
Free-Tool is adapting screen
A free-tool named “f.lux”, available for Windows, Mac and Linux is promising relief. This tool is adapting brightness and colour temperature of the screen to the course of the day and automatically to the time – from the cool blue of the morning to the warm yellow-red in the evening. User only have to fill in their whereabouts under “change settings”. If you don’t know your exact coordinates you can directly find them with Google maps and fill in afterwards. In case you have to do some work were colour fidelity of the screen is necessary, the tool may be paused for an hour just by clicking. Past experiences show that from computer work distressed eyes benefit from this tool, too.
Imagesource: @deathtothestockphoto
This post is also available in / Diesen Beitrag gibt es auch in:
German
Leave a Reply