Bright light from smartphones disturbs our sleep significantly

The light from the screens of smartphones seems to significantly worsen our sleep quality
Do you have more sleep problems and would you like to sleep through a night again? Then maybe you should spend less time on the mobile phone. Researchers now found that the time spent in front of the screen of mobile phones, especially at bedtime, is associated with a disturbed sleep pattern.

Researchers at the University of California, San Francisco found during an investigation that spending time in front of a screen on a smartphone seems to disturb our sleep. The physicians published the results of their study in the journal "Plos One".

In today's world, almost every person in Germany has a so-called smartphone. Experts found that using these phones resulted in decreased sleep quality. (Image: Ana Blazic Pavlovic / fotolia.com)

Use of the smartphone degrades sleep quality
Are you one of those people who spends a lot of time in front of the screen of his cellphone and has trouble sleeping at night? Then this is not really surprising, because researchers found a connection between the use of the smartphone and the quality of sleep. The more time someone spends in front of the screen of their mobile phone, the worse the quality of sleep will be, explains one of the study authors. Gregory Marcus from the University of California, San Francisco.

Use of electronic devices leads to difficulty falling asleep
There is an increasing body of evidence that the use of electronic devices leads to difficulty falling asleep. Earlier research has shown that using these electronic devices at night can cause problems. For example, it has been discovered that smartphones and tablets reduce the sleep quality of children and adolescents.

Light of the screens suppresses the hormone melatonin
Many of the devices emit strong blue light. Exactly this light seems to lead to the identified problems. The light suppresses the hormone melatonin, which usually rises a few hours before falling asleep. Melatonin is a signal to the body to prepare for sleep, the experts explain. The blue light seems to have an alarming effect on the brain. The review of content or e-mails could of course also cause stress, but also the simple use of the mobile phone play an important role here.

Subjects of the study answered questionnaires and used special app
For their study, the physicians examined the responses reported by adult volunteers themselves to an online survey. These were part of a completed international health study called Health eHeart. Participants also downloaded an app on their smartphone that automatically and continuously collected data on the number of hours spent in front of the screen. When participants used the app for at least 30 days, they were included in the analysis of the scientists.

Younger people spend more time in front of the screen
In total, 653 adults completed the study. The results show that participants spent an average of 3.7 minutes per hour on their smartphones. Younger people spend much more time on their phones, say the scientists.

Especially shortly before bedtime, the use of smartphones should be avoided
Another analysis included data from 136 participants. This study found that a longer time spent in front of the screen, a few hours before going to bed, was associated with a lower sleep time. On average, an extra minute of time spent in front of the screen was associated with a decrease in sleep duration of about five minutes. Marcus from the University of California, San Francisco.

Smartphone users stay awake longer before falling asleep
The team then looked at smartphone usage before bedtime at 56 participants for whom sufficient data was available. The results showed that increased pre-screen time in the hour before bedtime was associated with a greater proportion of awake bedtime. On average, every additional minute in front of the screen of the smartphone increases the sleep time by one and a half minutes, explain the experts. The study itself does not show whether the increased screen time leads to worse sleep or whether people with bad sleep use their smartphone more often. Further research should examine the impact of websites and apps (such as Facebook) on human sleep, say the physicians.

Technology needs to be optimized
"I'm a big fan of technology and think technology will help us solve many problems," Dr. Marcus. However, we should carefully consider how we can optimize the use of this technology and understand the implications of using it, the expert adds. The causality of the data suggests that the time spent in front of the screen of the smartphone, especially at bedtime, can be detrimental to a healthy night's sleep, adds Drs. Marcus added.

Effects of bad sleep
Bad sleep is associated with an increased risk of a number of health problems. These include, for example, obesity and an increased risk of stroke, explain the experts. For this reason, the impact of smartphones should be investigated more urgently. (As)