A recent study published in the open access journal PLOS detailed a quantitative relationship between smartphone usage and sleep quality. 761 participants recruited from Health eHeart participants (an online database of study volunteers) had their screen-time tracked over a period of 30-days. The object of the study was to identify associations between sleep and screen-time. The investigation used an app based tracker for smartphone usage, and surveys to identify sleep quality.
The average screen-time of participants was a median 3.7 minutes per hour. This is equivalent to an average screen-time of 1 hour and 29 minutes per day. Adjusting for age, sex, race, and sleep apnoea, poor sleep quality, increased sleep latency, and reduced sleep efficiency all had statistically significant associations with longer average screen-time during the reported sleeping period, and during the hour after bedtime. Reported sleep duration was not associated with the average screen-time during the sleeping period, nor during the three hours before bedtime.
Longer average screen-time was associated with shorter duration of sleep and reduced sleep efficiency. Given that screen-time after reported sleeping hours and near an individual’s bedtime had the greatest association with poor sleep quality, increased sleep latency, and reduced sleep efficiency; the relationship between overall smartphone use and sleep is likely driven by exposure near bedtime. This is fortunate news for smartphone users; as day time screen-time does not appear to influence sleep quality, latency or efficiency.
Christensen, MA, Bettencourt, L, Kaye, L, Moturu, S, Nguyen, K, Olgin, J, Pletcher, M, Marcus, G. Direct Measurements of Smartphone Screen-Time Relationships with Demographics and Sleep. PLOS One [Online]. Available at: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0165331 [Accessed 14 December 2016].
