It has long been recognized that
sleep deprivation is harmful to mental health. Recent investigations, however,
have shown that irregular sleep patterns — especially a pattern of regular
sleep deprivation followed by increased weekend sleep time, or “social jet lag”
— has an even greater adverse impact than sleep deprivation.
In order to help the citizens of
Taiwan improve their overall health by managing their sleep patterns, the
National Health Research Institutes asked Dr. Lin to develop a new app for
smartphones. The application tracks smartphone-use patterns to derive sleep
times and analyzes changes in sleep patterns. It has an accuracy of 90.4
percent for sleep-time estimation and a consistency of 87 percent for circadian
rhythm fluctuation, demonstrating the app’s reliability. It also displays sleep
patterns graphically, and notes how sleep patterns differ between weekdays and
weekends, helping users avoid social jet lag. The research behind the building
of this app was published in a top international journal, JMIR mHealth
and uHealth, in May 2019.
Research at the National Health
Research Institutes has shown that long-term irregular sleep patterns may
increase the risk of not only diabetes and cardiovascular disease but also of
cancer and mental illness. According to research published in JAMA Psychiatry, changes in activity
levels and sleep patterns are a greater predictor of manic episodes compared to
subjective mood changes. Sleep-pattern changes may be an important treatment
marker for mania, depression, schizophrenia, and other mental illnesses.
Before the invention of this app,
self-monitoring sleep patterns was difficult. Neither the wearable devices
currently on the market nor in-hospital sleep laboratory investigation (i.e.,
polysomnography) can attain both accuracy and wide accessibility. In a
one-month test of twenty-eight subjects, however, the Rhythm app achieved both
high accuracy in its monitoring of sleep patterns (90.4 percent) and
consistency (87 percent). The algorithm is able to accurately quantify weekend
sleep times, which is a feature that wearable devices on the market do not
have.
Certain occupations require
early-morning starts, which may cause sleep deprivation and lead to catch-up
sleep on the weekends, with late sleep times and late wake times. It is almost
as if a person shifted one whole time zone from Taiwan to Bangkok on weekends
and had to shift back on Monday. Research shows that social jet lag may
increase the risk of obesity, diabetes, and cardiovascular diseases. In 2017,
the American Sleep Association showed that one hour of social jet lag may
increase the risk of cardiovascular disease by 11 percent. In 2019, an
article in Current Biology showed
that sleep deprivation may cause reduced insulin sensitivity and raised glucose
levels, increasing the risk of diabetes. Social jet lag does not reverse the
effects of sleep deprivation and may even worsen insulin sensitivity.