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.

  Komono Town is a well-known spa and health resort in Mie Prefecture. Komono Town has been seeking ways to promote the activities of hot spring area and health resources in surrounding areas. As part of these efforts, Komono Town has developed town-walk programs to promote the health of local residents. In this study, focusing on effect of walking on relaxation, we compared levels of stress hormones and emotional scores obtained before and after walking.

  After giving their informed consent, adult participated in two walking programs, each for a distance of approximately 7 km. Salivary cortisol levels were measured before and after intervention. In addition, the Mood Check List-Short form. 2 (MCL-S.2) and a Visual Analog Scale (VAS) were used to rate emotions before and after intervention.

  In both programs, walking tended to lower levels of salivary cortisol than resting. Low levels of cortisol, an adrenocortical hormone released during a state of predominantly sympathetic nervous activity, are thought to reflect mental relaxation; our result implies that the walking program enhanced relaxation in subjects. In addition, both MCL-S.2 and VAS rating showed that the subjects tended to feel better, more relaxed and less anxious after intervention.

  These findings suggest that the walking programs are beneficial human body thorough, for example, enhanced relaxation.

Objectives: Radon is a major feature of radioactive springs. According to an official notification article in Japan, bathing in radioactive springs may alleviate the effects of hyperuricemia (gout), rheumatoid arthritis, and ankylosing spondylitis. This study focuses on changes in the body during the use of a low-temperature sauna at a radioactive hot spring.

Methods: In this study, we measured the core temperature, skin temperature, and skin blood flow, and performed an emotional assessment (Mood Check List-Short form.2 (MCL-S.2), Visual Analog Scale (VAS), and Numerical Rating Scale (NRS)) in individuals using a sauna at a radioactive spring. Eight healthy adults participated in this study. All participants partook in two sauna interventions, including one sauna with a high radon concentration (approximately 710 Bq/m³) and one with a low radon concentration (approximately 140 Bq/m³). The indoor temperature and relative humidity of the sauna room were approximately 38°C and 78%, respectively. All participants remained in the sauna room for 40 min, and then rested in an antechamber for 40 min.

Results and Discussion: Comparing the MCL-S.2 scores, a significant increase was observed in the pleasantness score in the radon intervention. In addition, after comparing the VAS scores, significant improvements in the feelings of coldness and stress were observed only in the radon intervention. Moreover, skin blood flow increased for a longer duration in the radon sauna intervention than the control intervention. The results suggest that using radon saunas gives rise to positive effects, including reducing coldness, feelings of stress, and promoting blood circulation.

  Objective: The aim of the present study was to investigate the effect of bathtub drowning on erythrocytes in victims.

  Methods: Thirty-nine consecutive victims with CPA were included in the present study and consisted of 16 males and 23 females, 8-95 years of age, median 78 years old. Data on the arrival examination were analyzed, which consisted of serum sodium (Na) and chloride (Cl), hematocrit (Ht)/hemoglobin (Hb) ratio, mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH). In addition, the changes of MCV level in accordance with treatment in two bathtub drowning victims, one who was resuscitated and the other who had been under treatment in our hospital, were compared with those in two water intoxication patients.

  Results: Of the 39 victims, 18 showed serum Na levels to be lower than normal range (NR) but no victim showed one higher than NR. In serum Cl level, 22 victims showed levels below NR but no one showed a level above NR. As to the value for the Ht/Hb ratio, the ratios were within NR in only three victims and were above NR in the rest. In MCH, three victims showed levels below NR and one victim showed a level above NR. In MCV, 16 victims showed levels above NR but no one showed a level below NR. The comparison of MCV between drowning victims and water intoxication patients pointed out a difference in the effect on treatment: in cases of drowning, MCV increased only on the day of the event and returned to baseline the next day, whereas in cases of water intoxication, MCV remained unchanged for a few days after treatment and then increased.

  Conclusion: It is well known that freshwater drowning induces both hyponatremia and hypochloremia, which are caused by water transferred from alveoli to blood vessels. The increased MCV in bathtub drowning victims is induced by the expansion of erythrocytes through lower osmotic pressure, which exceeds the decreased change in hematocrit due to hemodilution, although the mechanism of the change in MCV in water intoxication cases is not identified.