SEOUL, June 3 (Korea Bizwire) — Despite a gradual increase in sleep duration among Koreans, the prevalence of inadequate sleep persists, accompanied by a concerning decline in sleep quality. Imbalanced sleep patterns pose a significant risk to mental health.
The average amount of sleep South Koreans get has experienced a gradual increase over the past 15 years, yet it still falls short compared to the amount of sleep people are getting in other countries around the world.
Findings from a 2021 global sleep survey conducted by Philips revealed that Koreans average 6.7 hours of sleep on weekdays and 7.4 hours on weekends. In contrast, the global average stands slightly higher at 6.9 hours on weekdays and 7.7 hours on weekends.
However, the real concern lies in sleep satisfaction. While 55 percent of the global population were content with their sleep, a mere 41 percent of Koreans reported being satisfied, indicating a significant disparity.
The importance of cultivating healthy sleep habits cannot be understated, as sleep directly impacts brain health, cardiovascular health, and mental well-being, as highlighted in a recent study.
A comprehensive long-term study involving Koreans unveiled a strong correlation between total sleep duration and depression. Individuals who consistently slept between 7 and 8 hours displayed the lowest prevalence of depression.
Those who slept fewer or more hours faced a greater risk, with those sleeping less than 5 hours having a 3.08 to 3.74 times higher likelihood of experiencing depression compared to those who obtained the recommended amount.
The study, led by professors Yun Ji-Eun from the Department of Neurology at Soonchunhyang University Bucheon Hospital and Yun Chang-Ho from the Department of Neurology at Seoul National University Bundang Hospital, spanned a decade, from 2009 to 2018, and encompassed 2,836 and 2,501 participants, respectively.
Various sleep characteristics, including wake-up time, bedtime, total sleep time, circadian type, social jet lag, daytime sleepiness, insomnia, and sleep quality, underwent thorough examination and a correlation analysis with depression. The researchers released their compelling findings on Wednesday.
The researchers discovered that excessive sleep also contributes to a risk of depression. Those who slept more than 9 hours were 1.32 to 2.53 times more likely to develop depression than those who slept the recommended 7 hours. Additionally, daytime sleepiness, insomnia, social jet lag, and an evening circadian pattern demonstrated associations with increased depression risk.
The data also revealed that quality of sleep among South Koreans has declined over time. Over the span of a decade, the average total sleep time dwindled by 19 minutes, diminishing from 7 hours and 27 minutes to 7 hours and 8 minutes.
Sleep latency, or the time it takes to fall asleep, increased by 8 minutes on weekdays and 7 minutes on weekends, consequently reducing sleep efficiency. Utilizing the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality, with higher scores indicating poorer sleep quality, the study revealed a rise from 3.6 in 2009 to 3.8 in 2018, denoting an overall increase of 0.2 points compared to 2009.
Yun Ji-Eun, from Soonchunhyang University, expressed concern, stating, “With the aging population, increased shift work and night work, and the extensive use of digital media, sleep habits have become irregular, and sleep disorders are on the rise. It is imperative that we recognize the shifting sleep characteristics of Koreans as a social issue and make dedicated efforts to address it.”
Seoul National University’s Yun Chang-Ho further emphasized the potential repercussions of insufficient sleep duration and poor sleep quality, which can contribute to a range of diseases, including stroke and cardiovascular disorders. Yun highlighted the significance of attaining the appropriate duration, cautioning against sleeping less than 5 hours or exceeding 9 hours.
Bedtime behaviors significantly impact the quality of one’s sleep, and South Koreans are prone to indulging in smartphone usage before retiring for the night. This habit may have an adverse effect on sleep quality. Notably, a prior Philips study revealed that 51 percent of Koreans use their phones right before bedtime, compared to 46 percent globally.
Moreover, it is worth noting that Korean sleep duration has observed a gradual increase each year for the past 15 years. According to Dr. Jeon Jin-sun, a professor of neurology at Hallym University, who presented data at a symposium event in Korea on Sleep Day this year (March 19), the average sleep duration rose from 6 hours and 50 minutes (411.1 minutes) in 2004 to 7 hours and 15 minutes (434.5 minutes) in 2019—an increase of approximately 35 minutes.
Since 2009, the number of Koreans sleeping for 7 hours or more has surpassed half of the total population.
Dr. Jeon attributed this rise in sleep duration to shorter working hours and a cultural shift emphasizing work-life balance. Notably, the increased sleep duration is primarily a result of extended sleep on weekends.
Sleep holds a crucial role in the maintenance and enhancement of brain health. During sleep, specific brain regions responsible for memory consolidation are activated, aiding in the organization and storage of daily memories. Consequently, sleep deprivation heightens the risk of developing dementia, including Alzheimer’s disease.
One potential explanation for sleep’s impact on dementia lies in the “glial system,” a brain circulatory system that activates during sleep to eliminate toxins. Insufficient sleep can impede the clearance of these toxins, leading to a heightened risk of dementia.
Dr. Park Hye-ri, a professor of neurology at Ilsan Paik Hospital who also participated in the symposium, highlighted several habits that can promote better sleep and safeguard brain health among the elderly.
These habits include avoiding naps, alcohol, and smartphone use before bed, adhering to regular sleep and wake schedules, and increasing daytime activity. Given that the elderly are more susceptible to various sleep disorders, seeking consultation from a sleep specialist is crucial for those experiencing persistent sleep-related discomfort.
Lina Jang (firstname.lastname@example.org)