Reading can be harmful


Are you sleeping long enough? Unfortunately I don’t. Maybe it’s the rush of life and we just don’t have enough time to get a good night’s sleep.

But if you go to bed early and still don’t get enough rest, what’s the fault?

As suggested by German and American researchers in their latest study published in the well-known scientific journal PNAS, limit the use of electronics before going to bed — for example, do not read on a tablet.

Their study was based on an experiment: over a dozen healthy people aged around 25 spent several weeks in a medical facility. Everyone read daily in dimly lit rooms for four hours a day, going to bed at 10.00 p.m. During the first week, half of the volunteers read on iPads and the other half used paper books. In the second week, the groups changed.

The results confirmed the suspicions that have been talked about for some time. Tablet users fell asleep on average 10 minutes later than people reading traditional books, and their REM phase (when dreams occur) was 10% shorter. In tablet users, blood levels of melatonin, which is considered a sleep hormone and used to treat insomnia , were 55% lower than in those using paper books.

But the numbers are of secondary importance here. The key conclusion is that respondents reported subjective differences about their well-being. IPad users felt less sleepy in the evening and felt like they didn’t sleep long enough. Overall, they needed a bit longer to fully wake up the next morning.

In fact, this correlation between brightness levels and melatonin levels (and consequently sleep quality) was published some time ago, so why all the fuss? According to researchers, tablet displays do not emit enough light to influence the results.

The report’s authors suggested that it is not the amount of light that matters, but the quality of it. The iPad intensively emits short waves of the optical spectrum – they are on the edge between blue and blue on the rainbow (450 nm wavelength). This brightness is different from normal ambient light and has an effect  on melatonin levels.

You can say that there is a difference between laboratory research and reality. I doubt anyone reads something on an iPad every night for the same four hours and then goes to bed at exactly the same time.

It’s worth knowing, however, that the displays used in iPads, modern TVs, smartphones and computers have a lot in common. Of course, their diagonal sizes vary, but the spectral wavelength is very similar. The 450 nm wavelength jump present in all screens of this type  is the same  for both LCD screens and OLED displays.

Add to that the average amount of time people spend each day watching TV, working on laptops or using mobile devices, and things will get boring. Not to mention the younger users, completely immersed in the digital world.

Except for the lab rats , you think no one died from lack of sleep? It’s debatable.

According to the  American Academy of Sleep Medicine, 250,000 car accidents in the United States alone are caused by falling asleep at the wheel each year. The authors of the PNAS report also noted that cases of chronic melatonin stoppage that occur with night shifts may increase the risk of oncological diseases.

Okay, so what can we do for a better night’s sleep?

  1. First, limit the time you spend in front of the TV, at your laptop or playing in the evening.
  2. Lower the backlight level and lower the color temperature (ie „warm” the image). This way you can reduce the intensity of blue light six times. In addition, it is also worth adjusting the contrast to avoid eye strain.
  3. If you like reading, try turning your e-books into paper books or e-readers – they use passive screens that reflect light rather than emit it. For example, for e-ink readers that are more affordable.
  4. Think about light bulbs – the most natural light with a uniform spectrum comes from the oldest ones. Energy saving fluorescent and cold light led bulbs can emit different types of light , including light with undesirable jumps in the short wavelength portion of the spectrum. Also think about red leds that don’t contain the blue part of the spectrum.The craziest idea you can take in the event of severe sleep disturbances is wearing special glasses with orange lenses that eliminate the blue part of the spectrum. The effectiveness of this solution has been clinically proven  in many scientific studies. Such glasses are recommended,  for example, to those who work at the computer at night.