- Screen based devices cause sleep
- Varied results among researches on
the effect of tiny screens on sleep
- Present research concludes sleep
pattern not altered by pre-sleep screen exposure
- Daytime lighting maybe a solution
to bright screen associated sleep disturbances
Using a laptop,
computers, mobiles or other screen-based technologies just before going to bed could
affect your sleep pattern and make you feel less rested.
Several epidemiological studies have proved that screen based device exposure
before going to sleep causes sleep problems. These studies were done based on the effect of short wavelength enriched screens
and ambient lighting on pineal gland and melatonin secretion.
Melatonin is a
hormone involved in the daily sleep-wake cycle secreted by the pineal gland (generally at night). LED screens affect melatonin secretion and
thereby prolongs sleep onset, slow wave sleep and decrease time on rapid eye
‘Using your laptop, computer, mobiles or other screen-based technologies just before going to bed could make you feel less rested and disturb your normal sleep pattern. However a recent study shows that the quality of sleep does not differ post usage of such devices.’
Short Wavelength Enriched
Screen Exposure - Is It Really Deleterious?
were subjected to evening use of tablet computers for 5
consecutive days which showed that there is a late shift in pre-sleep melatonin
increase, increased sleep onset latency, decreased time in REM sleep and
increased tiredness and sleepiness in the morning.
contradictory results are seen in other similar studies. For example a
comparative study done between people using short wavelength enriched screen
containing tablet and tablets with short wavelength filter concluded that there
was no significant difference in the sleep pattern.
similar study on reading with iPad before sleep gave a comparable result, it
also showed that sleepiness
before turning off the lights and early
night slow-wave activity is reduced. This made the path for further research to
check on the age old fact about short wavelength enriched screens.
experimental research was conducted in Uppsala Biomedical centre, Sweden and
was published in Sleep Medicine
handed adults with normal eye sight, with no prior medical or psychiatry
illnesses, who have the habit of sleeping between 21.00 and 23.00 and waking up between 06.00 and 10.00
with a good 7-9hrs sleep were enrolled in the study.
Prior to reading
they were exposed to 6.5hrs of normal room light conditions following which
polysomnography was attached to them at 20.00 and
reading exercise was started at 21.15 under a reading lamp. Saliva melatonin
measurements were taken serially from 21.00 hrs, every
half hour for 2hrs lights were switched off at 23.15
for sleep. Participants sleepiness were rated using Karolinska Sleepiness Scale
(KSS). Melatonin levels were measured using commercially available immunoassay.
electroencephalogram and electrooculogram were used to monitor the sleep
pattern and measure the sleep onset latency, total sleep time, latency of
slow-wave sleep and time in each stage for sleep. Two participants could not be
included in the analysis of sleep due to technical issues.
LED Screen Usage Before Sleep
Does Not Affect Nocturnal Sleep
The results of
this study were little contrary to what was traditionally thought of about LED screen usage before
sleep. There was no difference in the baseline melatonin levels and the circadian rhythm
of melatonin secretion (melatonin
secretion and sleep increases as the evening progresses) between the two
personal experience all the individuals gave similar feedback of book reading and e-book reading on a
tablet. The evening tablet use did not affect the sleep onset,
sleep duration, or time spent in the different sleep stages and also time of
slow wave sleep latency, in contrast to the earlier studies.
explanation for these discrepant results across experiments, in our view, is
that bright light exposure during daytime similar to that employed in the
present study has previously been shown to attenuate the suppressive properties
of evening light exposure on melatonin levels," said lead study author Frida
Rangtell, a neuroscience researcher at Uppsala University in Sweden.
The subjective ratings of sleep by each
individual on the basis of time taken to fall asleep, sleep quality and morning
sleepiness did not differ between the two reading conditions i.e. evening
tablet reading did not affect the quality of sleep.
difference between the present study and the previous study was the duration
and timing of evening light stimulus with screen based devices. This could make
a difference in the melatonin levels and quality of sleep in both the studies
as the extent of blue light exposure plays a major role in this physiology.
in the study were the small sample size, the used bright light conditions are
different from the normal indoor light, short duration of exposure to screen
based devices and the fact that the previous light exposure was not taken into
"As most of us know, reading on tablets,
checking emails on phones, or watching late night TV are a chronic issue, and
unfortunately become part of our pre-sleep habits," said Karatsoreos, a
neuroscience researcher in Washington state university( not part of the
research team). This study seems to evaluate only short term single exposure to
bright light, further research is needed to study the effect of this common
ritual of regular continuous exposure.
5 Healthy Sleep Habits
1. Stick To A Schedule
- The same bedtimes and wake times should be maintained every day, even on weekends.This helps you to fall asleep and stay asleep the whole night.
2. Avoid Day Naps
- Power napping can help you through a hard day. However, naps that
go beyond 30 mins, can disturb your night time sleep and may leave you sleep
deprived the following day.
- A vigorous exercise routine is best for a restful and peaceful sleep.
4. Wake Up To Sunlight
- Dim bright lights during the evenings and expose yourself to
bright sunlight in the morning. This helps keep you refreshed and also regulates
your circadian rhythms.
- Turn off your computer and smartphones at least 1 hour before going to bed for a
good night's sleep.