Brain Sleep Co., Ltd. (Headquarters: Chiyoda-ku, Tokyo; CEO: Atsushi Hirota; hereinafter referred to as "Brain Sleep") has been conducting the "Sleep Standard Deviation®" survey since 2020 targeting 10,000 employed people (allocated by gender, age, and prefecture) in all 47 prefectures nationwide, and 2024 marks the fifth year. The sleep standard deviation is a method of comprehensively scoring productivity, stress level, risk of sleep apnea syndrome (SAS), and other factors in addition to items that directly assess sleep status, such as sleep habits and sleep debt. In the future, we will utilize the results of this survey to carry out various activities aimed at further improving sleep in Japan. Sleep Deviation Value® Survey Results Pagehttps: //brain-sleep.com/service/sleepdeviationvalue/research2024/ Survey results summary Brain Sleep has created the "Sleep Standard Deviation®" from various sleep-related scales, and has been working to understand the actual sleep conditions of Japanese people and to develop health management services for corporate employees. This time, we measured the 2024 version of the sleep standard deviation and clarified the characteristics of Japanese sleep in the following five new items. 1. Changes in sleep times in Japan 2. Relationship between productivity (economic loss) and sleep 3. The relationship between the number of days people feel sad about going to work and their sleep quality 4. Characteristics of the TOP 1,000 and WORST 1,000 sleep deviation scores Comment from Seiji Nishino / Chief Research Advisor of Brain Sleep, author of "The Stanford Way to Get the Best Sleep" This year's survey results also showed an upward trend in sleep duration in Japan, with sleep duration in 2024 increasing by 23 minutes compared to 2020. However, compared to the average sleep duration of OECD member countries, it is still 1 hour and 38 minutes shorter, and the ideal sleep duration is about 50 minutes longer. 70% of people felt that sleep affects productivity, and the economic loss of those with no issues with sleep quality was 890,000 yen per year, while those who need improvement lost 1.65 million yen per year, a difference of 760,000 yen. People with poor sleep deviation scores are characterized by short sleep duration and poor sleep quality, but many of them have long total working hours due to overtime work, and it was found that the rate of smartphone use before going to bed is extremely high. In order to improve corporate labor productivity, it has become clear that not only individual lifestyle improvements but also issues that the company as a whole must address, such as reducing overtime work. 1. Change in sleep time in Japan: +7 minutes compared to 2023. The difference from ideal sleep time is 50 minutes. The average sleep time for 10,000 employed people in 2024 was 6 hours and 50 minutes, the longest in the past five years of the survey. Compared to 2020, when the survey began, sleep time has increased by 23 minutes, but it is still overwhelmingly shorter than the average sleep time of 8 hours and 28 minutes in OECD member countries, and it can be said that Japan's sleep is still at the lowest level in the world. In addition, when the ideal sleep time was surveyed, it was found that there was a difference of 50 minutes between the actual sleep time and 7 hours and 40 minutes. In addition, the "Sleep Guide for Health Promotion 2023 (Draft)" published by the Ministry of Health, Labor and Welfare in December 2023 recommends that adults get at least six hours of sleep. However, in this survey, 23.7% of people slept less than six hours, suggesting that lack of sleep remains a major issue in Japan. *A one-way analysis of variance was performed on all data, and significant differences were confirmed (p<0.01). In addition, a Bonferroni-corrected t-test was performed to compare sleep time with the previous year, and significant differences were confirmed (both p<0.01). 2. Relationship between productivity (economic loss) and sleep: Poor sleep quality leads to high economic loss It has been reported in recent years that poor sleep quality has a significant impact on work performance and leads to losses for companies. It is said that many industrial accidents are caused by lack of sleep or sleep disorders. In this survey, we once again examined the relationship between productivity and sleep. In response to the question, "Does sleep affect productivity?" 70.0% of respondents answered "It has a strong effect" or "It has an effect," indicating that there is a growing understanding of the relationship between sleep and productivity. Furthermore, when the amount of economic loss*1 was investigated by sleep quality rank, a correlation was found between sleep quality and the amount of economic loss. It was found that the economic loss for people with a rank A sleep quality, who have no issues, was 890,000 yen per year, while for people with a rank D sleep quality, who need improvement, it was 1.65 million yen per year, a difference of 760,000 yen. This result suggests that improving sleep quality can reduce the amount of economic loss for employees, which could lead to improved labor productivity for companies. *1 Economic loss: The economic loss was calculated by multiplying the answer given when expressing one's own productivity on a scale of 0-100% by annual income. Sleep quality (rank): The answers to the original questions were scored and then converted into a four-level ranking system A to D. (A: No issues B: Mild issues C: Issues D: Needs improvement) *A one-way analysis of variance was performed to confirm the relationship between sleep quality and economic loss, and a significant difference was confirmed (p<0.01). In addition, a Bonferroni-corrected t-test was performed to compare ranks, and a significant difference was confirmed (both p<0.05). 3. Relationship between the number of days people feel depressed about going to work and sleep quality: People with poor sleep quality feel more depressed about going to work The relationship between mental health and long working hours has been attracting attention for some time, but recent research has reported that long working hours are not the direct cause of deteriorating mental health, but rather that lack of sleep resulting from long working hours is what causes the deterioration of mental health.*2 This survey looked into the relationship between the number of days people feel depressed about going to work and sleep. Approximately 60% of respondents said they felt depressed about going to work at least once a week, and of these, more than 20% said they felt depressed five or more days a week. In addition, people who felt depressed about going to work zero days (n=3,931) had an average sleep quality score of 76.6, but the average score decreased as the number of days they felt depressed increased, with a difference of 8.7 points compared to people who felt depressed five or more days a week. However, this survey did not find a similar relationship between the number of days people felt depressed about going to work and the amount of sleep they got. * Multiple comparisons were performed using the Games Howell method, and significant differences were confirmed between 0-1 days and 1-2 days (both p<0.01). *2 Tenshi Watanabe, et al. https://www.mdpi.com/1660-4601/19/11/6715 4. Characteristics of the TOP 1,000 and WORST 1,000 sleep deviation scores When we compared the sleep duration, sleep quality, sleep habits, and work styles of the 1,000 people with the top sleep scores and the 1,000 people with the worst sleep scores, we found differences in many areas. First, in terms of average sleep time, the TOP1,000 had a sleep time of 7 hours 12 minutes, which was 22 minutes longer than the overall average of 6 hours 50 minutes, indicating that they were getting a relatively sufficient amount of sleep. On the other hand, the WORST1,000 had a sleep time of 6 hours 32 minutes, which was about 18 minutes shorter than the overall average. There was a 28.6 point difference between the TOP1,000 and WORST1,000 in terms of sleep quality score. Among the sleep habits that affect sleep quality score, a clear difference was confirmed especially in the "rate of smartphone use before going to bed." The rate of smartphone use before going to bed in the TOP1,000 was low at 7.7%, while the rate in the WORST1,000 was 50.5%, more than half. When it comes to smartphone use, it is often said that blue light has a negative effect, but recently blue light has been cut on screens, and it tends to be the brain waking up when checking SNS or email that has a greater impact on sleep than the effects of blue light. This can lead to difficulty falling asleep and waking up in the middle of the night, which can lead to poor quality sleep. Differences were also found in working styles. Between the TOP1,000 and WORST1,000, the total working hours differed by 1 hour 20 minutes, and especially the overtime hours differed by 1 hour 33 minutes, confirming that the WORST1,000 work longer hours in both cases. When people work long hours, they tend to cut down on their sleep time, which makes them more susceptible to sleep deprivation. Furthermore, the proportion of shift workers, which is an irregular working style, was 8.5% higher in the WORST1,000. * A t-test was performed and the difference was confirmed to be significant (p<0.01). Sleep Standard Deviation® Survey Results Page https://brain-sleep.com/service/sleepdeviationvalue/research2024/ In addition to overall sleep, in 2024 we focused on the sleep environment. In addition to the announced content, we can provide data such as who you sleep with, temperature and humidity, sleeping environment preferences, bathing methods, etc. by industry, occupation, gender, age, and region. *When using the content of this survey, please be sure to cite "Sleep Standard Deviation Score® 2024 Brain Sleep Survey" as the source. [Survey Overview] Survey method: Web survey Target area: Nationwide Target conditions: Male and female Sample size: n=10,000ss Survey period: January 2024 *When comparing sleep deviation values and scores between groups, one-way analysis of variance or t-tests were performed, and differences with a significance level of 5% or less were determined to be statistically significant and are reported here. *This survey has changed some subjects and survey items from last year. What is Sleep Standard Deviation®? This system creates a set of questions that quantify the subjective evaluation of sleep from a wide range of perspectives, including subjective symptoms and sleep habits, and then quantifies them as a "deviation score" familiar to Japanese people, making it possible to grasp the relative sleep state of the Japanese population as a whole. It is being deployed in the field of verification and research of sleep-related products and services, and as a corporate health management service called "Sleep Deviation Score for Biz." It can be widely used as a subjective evaluation of sleep. Brain Sleep Health Management Consulting: https://brain-sleep.com/service/sleepdeviationvalue/
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