Authors (including presenting author) :
Wong WY (1)
Affiliation :
(1) The Hong Kong Polytechnic University
Introduction :
A good night sleep is essential to our physical and mental health. Previous studies showed that the use of electronic media, with the emitting light in the blue spectrum, suppresses the secretion of melatonin which in turn decreases sleepiness. This study investigated the effects of bedtime mobile phone use of adults on sleep quality measured by commercially available sleep tracker, Fitbit Charge 3.
Objectives :
To identify whether using the "Night Shift" mode of iOS will alter the effects of bedtime mobile phone use on sleep quality.
Methodology :
Thirty health adults (n=30), 30-45 years old, 23 females and 7 males, were recruited to take part in this study. Within-subject approach was adopted. The experiment lasted for three nights. During the experimental days, subjects were asked to wear the sleep tracker, Fitbit Charge 3, to monitor their sleeping profile. Day 1 is the 'adapting night' for subjects to get used to wearing the tracker to sleep. On Day 2, subjects had needed to switch on the "Night Shift" mode to the "warmer" end from 6pm to 6am the next morning with full brightness. On Day 3, the "Night Shift" function is switched off while the screening is kept at full brightness for the whole day. During Day 2 and Day 3, subjects were asked to watch a 20-25-minute-long video and then finish an online sleep diary (5-10 minutes long) after light out in their own bed. Time to fall asleep, durations and percentage distributions of different sleep stages, Number of Awakening, Total Sleep Time, Time In Bed and subjects' self-reported sleepiness were analyzed.
Result & Outcome :
Subjects reported statistically significant higher level of subjective reported sleepiness before sleep (p=0.0308), higher percentage of REM sleep (p=0.0398), higher percentage of Deep sleep (p=0.0055), and lower percentage of Light sleep (p=0.0012) during the night using the Night Shift mode than the night without Night Shift mode.
