New York, Nov 10 (IANS): If you want to improve your sleep, better cut down on smartphone use near bedtime, suggests a new study that found longer average screen-time is associated with poor sleep quality and less sleep overall.

Poor sleep is associated with health conditions such as obesity, diabetes and depression.

"Exposure to smartphone screens, particularly around bedtime, may negatively impact sleep," the study said.

For the study, Matthew Christensen from the University of California - San Francisco, US, and colleagues sought to test the hypothesis that increased screen-time may be associated with poor sleep by analysing data from 653 adult individuals across the US.

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 sleep quality.

The researchers found that each participant totalled 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 participants' bedtime, according to the study published in the journal PLOS ONE.