Frequent bathtub bathing (BB) improves sleep quality and mental health of middle-aged and older Japanese individuals. This study investigated the chronic effects of BB with and without a bath additive (bathtub bathing with KIKIYU [BBK]) in healthy young adults. The study involved healthy young adults who habitually showered, as opposed to bathing. Nineteen participants were randomly assigned to either the BB or BBK groups for 14 consecutive nights. After a 2-week washout period (shower bathing), the participants were asked to switch their bathing styles (a crossover design). The artificial bath additive for the BBK group contained inorganic salts and carbon dioxide. The participants were evaluated by using the Oguri-Shirakawa-Azumi Sleep Inventory-Middle-aged version (OSA-MA) and 1-ch sleep electroencephalography (EEG) for sleep quality, the Profile of Mood States (POMS), Self-rating Depression Scale (SDS), and Apathy Scale (AS) for mental conditions.  Sleepiness on waking and refreshing scores in the OSA-MA significantly differed between the shower bathing and BBK groups. EEG results did not significantly differ among the bathing styles. Vigor T-score and total mood disturbance (TMD) scores showed significant differences in the two bathing groups (shower vs. bathing), and fatigue T-score was significantly lower in the BBK group compared with both the BB and shower groups. SDS score was significantly lower in the BBK group compared with the shower group. AS score was significantly lower in the two bathing groups (shower vs. bathing).   The OSA-MA score was possibly influenced by vasodilatation and circulation by using carbon dioxide and keeping the body warm after bathing by using inorganic salts. The OSA-MA score was possible also affected by fatigue alleviation and maintenance of vitality by using a citrus lemon scent and yellow-green hue. Furthermore, frequent body heating affects the central nervous function related to mood and emotion.  Based on these results, we can conclude that BB and BBK prior to shower bathing improved the mental health of the young adults in this study.

Introduction: Some students take showers instead of baths for economic reasons or because they dislike cleaning the bathtub. The purpose of this study was to examine the effect of bathing routines on students’ working efficiency. Subjects: Seventeen (six male and 11 female) healthy young students (19.6 ± 0.7 years old, mean ± SD) who habitually took showers instead of baths participated in this study. Informed consent was obtained from all the subjects and the study was approved by the Ethics Committee of Kumamoto Health Science University. Method: Subjects were randomly assigned into two groups. The subjects in the first group (bathtub bathing [BB]) were immersed to the supraclavicular level in their home bathtub and instructed to rest for 10 minutes with the temperature regulated at 41°C. The subjects of the second group (whole-body warming after BB [BBW]) followed the same bathing protocol and then rested in a sleeping bag and sheet for 30 minutes to keep their bodies warm. Each period was carried out over 2 weeks in a cross-over design. Washout periods were 2 weeks long. The evaluation items of this study included the obstructive sleep apnea (OSA) sleep inventory MA version (OSA-MA), a questionnaire containing a visual analog scale (VAS) to judge the subjective bathing effect, profile of mood states, salivary stress marker (α-amylase), and the Purdue Pegboard test. These tests were evaluated before and after the BB sessions, BBW sessions, and washout interval for a total of four times in a 6-week period. Result: Participants tended to report a better sleep feeling on the OSA-MA after the BB or BBW sessions than after showering. There were significantly better changes in both the BB and BBW in the VAS for bathing effect in terms of “Sense of deep sleep,” “Body fatigue,” “Light feeling of the body” than after a shower. The mean α-amylase value in the saliva of the BBW group participants was significantly lower than that after showering. The mean Purdue Pegboard test scores of both the BB and BBW sessions were significantly higher than that after the shower. Discussion: Sleep quality seemed to be more improved after BB or BBW than after showering, perhaps due to reduced stress. Work efficiency also increased in the BB and BBW groups.

Objective: The purpose of this study was to examine the effects of bathtub bathing （BB） on sleep and working efficiency of healthy young adult students. Furthermore, the effects of BB and prolonged increased body temperature from the use of insulating sheets and sleeping bags after BB （warming after BB: BBW） on sleep and working efficiency were investigated. Subjects: Eighteen （six males, 12 females） healthy young students （19.6±0.7 years old, mean±SD） who habitually took showers instead of baths participated in this study. Informed consent was obtained from all of the subjects, and the study was approved by the Ethics Committee of Kumamoto Health Science University. Methods: Subjects were randomly assigned to two groups （n＝9 in each group）. The subjects in the BB group were immersed in their home bathtub to the supraclavicular level and instructed to rest for 10 min with the temperature regulated at 41°C. The subjects in the BBW group followed the same bathing protocol, and they then rested in a sleeping bag and sheet for 30 min in order to keep their bodies warm. The length of each study period was 2 weeks in a crossover design. After the 2-week-long washout periods, the subject groups were switched. The subjects were evaluated with the Oguri-Shirakawa-Azumi sleep inventory, MA version （OSA-MA）, which utilizes a visual analog scale （VAS） with which subjects rate their sleep when they wake up, and Purdue Pegboard Assembly test. These tests were employed before and after the BB and BBW sessions, resulting in four testing periods in the 6-week period. Results: Sleep rating on the OSA-MA was no significant difference in both the BB and BBW groups compared to ratings recorded after showering. The subjects in the BB and BBW groups had significantly increased VAS ratings for “Feeling of sound sleep,” “Refreshing,” and “Lightness of the body” compared to the ratings after showering. The mean Purdue Pegboard test scores of the subjects in both the BB and BBW groups were significantly higher than those recorded after showering. Discussion: Changing bathing style from shower to BB or BBW improved the working efficiency of students on the Purdue pegboard test. BB and BBW resulted in soothing effects owing to improvements in the subjects’ quality of sleep.

Objective: The purpose of this study was to clarify the chronic effects of bathtub bathing (BB), whole body warming after bathtub bathing (BBW), and bathtub bathing with herbal extracts (BBH) on the mental condition of healthy young persons. Subjects and Methods: Experiment 1: Eighteen (6 male and 12 female; age: 19.6±0.7 years, mean ± SD) healthy young persons who were taking a shower habitually but not bathtub bathing participated in this study.   From November 2012 to December 2012, subjects were randomly assigned into two groups (each 3 male, 6 female): those who had BB or 30-min BBW 14 times for 14 consecutive nights during a 2-week period. After a 2-week washout period, subjects were asked to switch their bathing conditions (a cross-over design). Experiment 2: Twenty (8 male and 12 female; age: 21.3±1.6 years, mean ± SD) healthy young persons who were taking a shower habitually but not bathtub bathing participated in this study.   From October 2013 to November 2013, subejects (4male and 6 female) were randomly assigned to undergo BB or BBH.   The herbal extract contained Dong dang gui (Japanese Angelica Root), Chimpi (Citrus Unshiu peel), Chamomilla recutita, and ginger extracts.   After a 2-week washout period, subjects were asked switch to the other bathing condition (a cross-over design).   All participants provided informed consent for participation in these studies, and these studies were approved by the Ethics Committee of the Kumamoto Health Science University.   The subjects immersed their bodies up to the supraclavian for 10 min, in tap water adjusted to a temperature of 41 °C in their bathtub at home. The subjects’ mental conditions were assessed using Profile of Mood States short version questionnaire.   The differences in the effect of BB and BBW, as well as those of BB and BBH on the subjects’ mental conditions and their mental conditions pre-BB and post-BB, pre-BBW and post-BBW, pre-BBH and post-BBH were analyzed using Wilcoxon’s signed-rank sum test. Results: The points for depression-dejection, fatigue, and confusion in those who had BBH significantly converged to the median average (50 points) compared to the points in those who had BB.   The points for anger-hostility before BBW and BBH significantly converged to the median average (50 points) after BBW and BBH, and there were no significant differences in points before and after BB. Conclusions: The subjects’ anger-hostility was influenced by body warming in BBW and the vasodilatory components of the herbal extracts.   The subjects’ depression-dejection and fatigue was influenced by the fragrance and color of herbal extracts.

BACKGROUND: The burden of dementia is growing rapidly and has become a medical and social problem in Japan. Prospective cohort studies have been considered an effective methodology to clarify the risk factors and the etiology of dementia. We aimed to perform a large-scale dementia cohort study to elucidate environmental and genetic risk factors for dementia, as well as their interaction. METHODS: The Japan Prospective Studies Collaboration for Aging and Dementia (JPSC-AD) is a multisite, population-based prospective cohort study of dementia, which was designed to enroll approximately 10,000 community-dwelling residents aged 65 years or older from 8 sites in Japan and to follow them up prospectively for at least 5 years. Baseline exposure data, including lifestyles, medical information, diets, physical activities, blood pressure, cognitive function, blood test, brain magnetic resonance imaging (MRI), and DNA samples, were collected with a pre-specified protocol and standardized measurement methods. The primary outcome was the development of dementia and its subtypes. The diagnosis of dementia was adjudicated by an endpoint adjudication committee using standard criteria and clinical information according to the Diagnostic and Statistical Manual of Mental Disorders, 3rd Revised Edition. For brain MRI, three-dimensional acquisition of T1-weighted images was performed. Individual participant data were pooled for data analyses. RESULTS: The baseline survey was conducted from 2016 to 2018. The follow-up surveys are ongoing. A total of 11,410 individuals aged 65 years or older participated in the study. The mean age was 74.4 years, and 41.9% were male. The prevalence of dementia at baseline was 8.5% in overall participants. However, it was 16.4% among three sites where additional home visit and/or nursing home visit surveys were performed. Approximately two-thirds of dementia cases at baseline were Alzheimer's disease. CONCLUSIONS The prospective cohort data from the JPSC-AD will provide valuable insights regarding the risk factors and etiology of dementia as well as for the development of predictive models and diagnostic markers for the future onset of dementia. The findings of this study will improve our understanding of dementia and provide helpful information to establish effective preventive strategies for dementia in Japan.
Aged ; Alzheimer Disease/genetics* ; Dementia/genetics* ; Environment ; Female ; Humans ; Incidence ; Japan/epidemiology* ; Male ; Middle Aged ; Prevalence ; Prospective Studies ; Risk Factors