smartphone screens is associated with lower sleep quality, according to a study
published in the open-access journal PLOS ONE by Matthew Christensen
from the University of California, San Francisco, USA, and colleagues.
are increasingly becoming part of everyday life, but questions remain about the
effects of frequent use on sleep. Poor sleep is associated with health
conditions such as obesity, diabetes and depression.
‘On an average, smartphones being activated for 3.7 minutes in each hour is associated with poor sleep quality and less sleep overall.’
and colleagues sought to test the hypothesis that increased screen-time may be
associated with poor sleep by analyzing data from 653 adult individuals across
the United States participating in the Health eHeart Study.
Participants installed a smartphone application which recorded their
screen-time, defined as the number of minutes in each hour that the screen was
turned on, over a 30-day period. They also recorded their sleeping hours and
researchers found that each participant totaled an average of 38.4 hours over
this period, with smartphones being activated on average for 3.7 minutes in
each hour. Longer average screen-time was associated with poor sleep quality
and less sleep overall, particularly when smartphones were used near
state that their study is the first to measure smartphone exposure
prospectively, but caution that the study also had some important limitations,
including the self-selection of study participants and self-reporting of data.
the authors' findings cannot show causation or exclude the
"effect-cause" that poor sleep could lead to more screen time, the
association they found could fit with the theory that bedtime smartphone use
may negatively impact sleep.