Brain Sleep Co., Ltd. (Headquarters: Chiyoda-ku, Tokyo, CEO: Kosuke Michibata, hereinafter referred to as "Brain Sleep") has conducted a test (hereinafter referred to as "this project") on the effect on sleep of "Washi Yarn Bedding Covers" that are covered with "WAGAMI", a Japanese paper yarn that was jointly developed with Toshima Co., Ltd. (CEO: Hanshichi Toshima, Naka-ku, Nagoya, hereinafter referred to as "Toshima"), which aims to propose a comfortable lifestyle, with technical support from ITOI Lifestyle and Culture Research Institute Co., Ltd. This test confirmed that differences in the materials of the bedding covers may contribute to improvements in sleep latency*1 and bed exit latency*2. *1 Sleep latency: The time it takes to fall asleep after getting into bed *2 Bed latency: The time from the last awakening to getting up Background of the Brain Sleep x Teshima initiative In order to solve the sleep issues in Japan, where sleep time is the shortest among OECD member states, Brain Sleep develops products based on sleep medicine, disseminates accurate sleep information, and supports the acquisition of accurate evidence regarding sleep. Since August 2021, Toyoshima has been developing washi thread material using the newly developed DIRECT washi thread manufacturing equipment*3 with the support of ITOI Lifestyle and Culture Research Institute Co., Ltd. From the beginning, they thought that bedding would be the best way to take advantage of the characteristics of washi paper, such as its water absorption and quick drying, smooth feel, non-stickiness even when sweating, moisturizing properties, and deodorizing properties, and they have succeeded in developing the ideal material for bedding. This time, at the request of Toyoshima, who wanted to quantify the depth and comfort of sleep and create products that lead to comfortable sleep, Brain Sleeve conducted a verification of the effect of washi material on sleep. *3 The world's first washi thread manufacturing machine, patented by ITOI Lifestyle Research Institute (Patent No. 6822708). This machine can make thread by slitting thin base paper (10gr/m2) thinly (without winding the slit thread) and directly twisting it. Tested product: Features of bedding cover made from washi paper The features of the washi yarn bedding covers developed by Toyoshima are as follows: The washi yarn bedding cover is designed with a fabric structure that covers the surface with washi yarn "WAGAMI". Washi paper has functions such as "cool in summer and warm in winter" and has high moisture absorption and release properties. In addition, waste materials discharged during logging in managed forests are used as wood pulp, which is the raw material for washi paper. The polyester that is twisted with washi paper is also made from recycled PET materials. This bedding cover combines functionality and sustainability. Verification Content In this experiment, we compared the above-mentioned "Japanese paper bedding cover" with a general "cotton-polyester bedding cover" to examine the effect that different bedding cover materials have on sleep. Six men and women in their 20s to 60s slept in two different types of bedding covers, a Japanese paper bedding cover and a general cotton-polyester bedding cover, in the same environment (specified temperature and humidity)*4, and their sleep state was measured. The two bedding options covered are as follows: 1. Washi yarn bedding covers: pillowcases, sheets, and duvet covers made from washi yarn 2. Cotton-polyester bedding covers: Commercially available products made of cotton and polyester (pillowcases, sheets, duvet covers) (Pillowcases and sheets: 70% cotton/30% polyester, duvet cover: 50% cotton/50% polyester) Sleep status was assessed using an activity meter as an objective indicator and the OSA Sleep Questionnaire (MA version) as a subjective indicator. *5 We also used a thermometer and hygrometer to measure the temperature and humidity inside the bed. *4 A room with temperature and humidity adjusted to approximately 27°C and relative humidity (RH) of 80%. *5 A statistical scale of sleep sensation, a common sleep evaluation method proposed by the Japan Sleep Improvement Council. It is a psychological scale that evaluates sleep reflection upon waking, and is assessed by 16 questions categorized into five factors: "sleepiness upon waking," "falling asleep and staying asleep," "dreaming," "recovery from fatigue," and "sleep time." Test Results Result 1: Objective data from an activity monitor Compared to the cotton-polyester bedding cover group, the washi thread bedding cover group showed a tendency for sleep latency and bed-getting latency to be shortened. In addition, although it was not statistically significant, the shortened sleep latency and bed-getting latency suggested the possibility of improving sleep efficiency*6. Therefore, it was found that the use of washi thread bedding covers tends to improve the ease of falling asleep and waking up. *6 Sleep efficiency: The ratio of time spent asleep (excluding time awake during the night) to time spent in bed Result 2: Objective data from in-bed environment measurements No difference was observed in the amount of change in temperature and humidity between the cotton-polyester bedding cover group and the washi paper thread bedding cover group. On the other hand, when comparing the number of times that the temperature inside the bed fluctuated significantly to evaluate the number of times that some movement that caused discomfort during sleep occurred, it was found that the number of fluctuations tended to be less in the washi thread bedding cover group than in the cotton-polyester bedding cover group. From this result, it is believed that the functional features of the washi thread bedding cover, such as its quick-drying and moisture-absorbing properties, reduced discomfort while sleeping. Result 3: Subjective data from a questionnaire using VAS In this study, the OSA Sleep Questionnaire (MA version) was used for subjective evaluation. The results showed that the group using the washi yarn bedding cover had a significantly higher score for the "fatigue recovery" category compared to the group using the cotton-polyester bedding cover. There was also a tendency for improvement in the "ease of falling asleep." From this, it can be inferred that the washi yarn bedding cover improved the quality of sleep and led to recovery from fatigue after waking up. Discussion of results As a result of the above verification, it was confirmed that "washi yarn bedding covers" have the potential to contribute to 1) helping people fall asleep more easily and 2) improving the quality of their sleep compared to common "cotton-polyester bedding covers." ① The results of the sleep index and subjective assessment confirmed that there was a tendency for the ability to fall asleep to improve. ② Temperature and humidity measurements, sleep index, and subjective evaluations suggested that the quick-drying properties of the washi yarn bedding covers may reduce discomfort on the body surface and make sleeping easier, thereby reducing fatigue and improving the feeling of waking up refreshed. Test Overview Subjects: 6 men and women in their 20s to 60s Test method: Crossover test Measurement items: Activity level, questionnaire evaluation using the VAS (Visual Analogue Scale), temperature and humidity in bed Test environment: Temperature and humidity of approximately 27°C and 80% relative humidity (RH) Test items: - Washi yarn bedding covers: pillowcases, sheets, and duvet covers made from washi yarn - Cotton-polyester bedding covers: Commercially available products made of cotton and polyester (pillowcases, sheets, duvet covers) (Pillowcases and sheets: 70% cotton/30% polyester, duvet cover: 50% cotton/50% polyester) [Comment from Brain Sleep (Chief Research Advisor/Seiji Nishino)] It is said that sleep is fragile. External factors such as the bedroom environment, internal factors such as anxiety and tension, and physical factors such as pain can all prevent good sleep. It has been pointed out that the bedroom and bedding environment can affect sleep, especially in the hot and humid Japanese summer. This test showed that using bedding covers made from washi yarn, which have excellent quick-drying and moisture-absorbing properties, tended to improve the ease of falling asleep and waking up, and participants were aware of their "recovery from fatigue." This not only reaffirms the importance of bedding in getting a good night's sleep, but also opens up possibilities for the application of new materials to bedding, which we believe to be very interesting results. <Mr. Seiji Nishino> Professor of Psychiatry at the Stanford University School of Medicine and Director of the Stanford University Sleep and Biorhythm Research Center Founder and Chief Research Advisor, Brain Sleep Inc. Certified Qualifications: Mental Health Designated Physician, Japan Society of Sleep Research Specialist, Industrial Physician, Physician, Doctor of Medicine ■ Joint verification partners Toyoshima Co., Ltd. President and CEO Hanshichi Toyoshima 2-1, Kanda Iwamotocho, Chiyoda-ku, Tokyo 101-0033 TEL: 03-4334-6100 URL: https://www.toyoshima.co.jp/
Log in
