SLEEP and SMARTPHONE RESEARCH

WE ARE LEARNING OF THE IMPORTANCE OF SLEEP IN RECOVERY from exercise, especially intense exercise. Athletes of all sports including running are paying more attention to sleep quantity and quality.

Daily exposure to smartphone screens has been suggested as having a negative effect on sleep, and scientists are attempting to help sort out the particulars.  The AMA Morning Rounds edition of November 10, 2016 lead with an item discussing the results of a study on the effect of smartphone screen time on sleep quality. The research was recently published in PLoS ONE, “Direct Measurements of Smartphone Screen-Time: Relationships with Demographic and Sleep” by Matthew A. Christensen and colleagues at the University of California San Francisco.

These scientists performed an analysis of 653 interested participants 18 years of age and older who were enrolled in a larger study. Place of residence included all of the 50 states; 23% were from California. Both males and females were represented.

Sleep time over a 30-day window was continuously measured by an Android-based mobile phone app. Data on total and average screen time, specifically during self-reported bedtime hours was computed and analyzed. A survey was used to obtain demographic and medical information and sleep habits. Only 56 participants had both 1) completed the survey and 2) submitted all possible screen time data.

Results showed that the “median total screen time over 30 days was 38.4 hours, average screen time was a median 3.7 minutes/hour. Longer average screen time was associated with shorter sleep duration and worse sleep efficiency.”

In the AMA item a CNN report quoted Gregory Marcus, MD, the study’s lead author, who said, ‘When we looked at smartphone use around the time when participants reported they went to bed, more smartphone use around that time in particular was associated with a longer time to fall asleep and worse sleep quality during the night.’”  

The study’s discussion explains further. “That increased screen time in the hour of and after bedtime, but not the hour before was associated with greater sleep onset latency agrees with the notion that screen use before attempting to fall asleep may be particularly problematic”.

The good news was that total smartphone screen time was NOT associated with physical activity level or BMI (Body Mass Index), unlike TV time; the authors thought this was due to smartphone “functionality” and use of these devices during physical activity. Of interest, although “searching for medical information was one of the most common activities carried out” with these devices, “none of the medical conditions evaluated were associated with average screen time.” Guess we aren’t as ill as we fear!

Research papers nearly always discuss what limitations exist in the study’s construction and conduct. The obvious one in this study is that only Android phone users could participate; no iPhone users were included. The relative age of the study participants was older (early 30’s to 60’s), and there was a greater proportion whites and females, and those who are better educated and wealthier compared to the US census population.  Participants were self-selected (not randomly picked) from the population and were already part of an online health study.

Overall this seems to be encouraging information. Many of us must use time after work and dinner to manage schedules and finances, answer personal emails, shop, conduct correspondence, and keep up with our social circles and local and world events. Fewer people rely on desk top or even lap top computers, and find it easier to work on smartphones as we commute, run errands, and perform household and child- and pet-care duties.

This study seems to indicate that ONLY the time during and after what is considered our “bed time”, is smartphone screen viewing likely to adversely affect sleep quality. Once the screen is dark, it should stay dark. A good discipline might be to complete all phone-work before changing into night clothes, cleaning teeth, and getting into bed.
 
RUN HAPPY!
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https://www.runtastic.com/blog/en/nutrition-wellness/workout-month-yoga-bedtime-relax-sleep/

 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0165331