An Evidence-map Proposal about the Risk of COVID-19 Infection in Balneotherapy, Based on Published Literature in 2020-2021 / 日本温泉気候物理医学会雑誌

  The primary objective of this study was to collect evidence that individuals who use hot spring facilities and public baths have a low risk of being infected with COVID-19. The secondary objective was to comprehensively summarize the research issues that remain to be explored in the field of balneology considering results of previous research.  Literature databases used were CINHAL, Cochrane Library (Clinical Answer, Cochrane Protocol, Cochrane Review, Editorials, Special Collections, Trials), Ichushi Web (in Japanese), MEDLINE, and Web of Science Core Collection. For each database, we selected results from the time it was opened through July 26, 2021. When intervention studies and experimental were searched, the following modified PICOS was used the following: P (Participant: no restrictions on the presence or absence of illness), I (Intervention: normal breathing or intentional sneezing, coughing, conversation), C (Comparison: no restrictions), O (Outcome: markers that simulate the flow of indoor air, the dynamics of droplets, and droplets in bathrooms and dressing rooms), and S (Study design: including intervention studies and experiments without a control group). For observational studies, PECOS included: P (participants: unlimited with or without disease), E (Exposure: public bathing facility), C (comparison: unrestricted), and S (study design: cross-sectional study, cohort study, and case-control study).  For the primary objective, no studies met the eligibility criteria, and at the time of this study there was no evidence that the use of hot spring facilities or public baths presented a low risk of being infected with COVID-19. Regarding the secondary objective, there were 15 relevant studies. In the context of a society that is strongly influenced by COVID-19, our literature review identified four research issues: “A. Use of hot spring facilities and public baths has a low risk of COVID-19 infection”, “B. The quality of hot springs and the room temperature and water temperature of public baths make SARS-CoV-2 inactivate/attenuate”, “C. Hot spring facilities, public baths, bathing habits at home lead to prevention of COVID-19 and alleviation of symptoms”, “D. Bathing for survivors of COVID-19 is effective for various rehabilitation of patients”. Suitable research approaches for each issue would be required in order to grasp each evidence.

An Evidence-map Proposal about the Risk of COVID-19 Infection in Balneotherapy, Based on Published Literature in 2020-2021 / 日本温泉気候物理医学会雑誌

  The primary objective of this study was to collect evidence that individuals who use hot spring facilities and public baths have a low risk of being infected with COVID-19. The secondary objective was to comprehensively summarize the research issues that remain to be explored in the field of balneology considering results of previous research.  Literature databases used were CINHAL, Cochrane Library (Clinical Answer, Cochrane Protocol, Cochrane Review, Editorials, Special Collections, Trials), Ichushi Web (in Japanese), MEDLINE, and Web of Science Core Collection. For each database, we selected results from the time it was opened through July 26, 2021. When intervention studies and experimental were searched, the following modified PICOS was used the following: P (Participant: no restrictions on the presence or absence of illness), I (Intervention: normal breathing or intentional sneezing, coughing, conversation), C (Comparison: no restrictions), O (Outcome: markers that simulate the flow of indoor air, the dynamics of droplets, and droplets in bathrooms and dressing rooms), and S (Study design: including intervention studies and experiments without a control group). For observational studies, PECOS included: P (participants: unlimited with or without disease), E (Exposure: public bathing facility), C (comparison: unrestricted), and S (study design: cross-sectional study, cohort study, and case-control study).  For the primary objective, no studies met the eligibility criteria, and at the time of this study there was no evidence that the use of hot spring facilities or public baths presented a low risk of being infected with COVID-19. Regarding the secondary objective, there were 15 relevant studies. In the context of a society that is strongly influenced by COVID-19, our literature review identified four research issues: “A. Use of hot spring facilities and public baths has a low risk of COVID-19 infection”, “B. The quality of hot springs and the room temperature and water temperature of public baths make SARS-CoV-2 inactivate/attenuate”, “C. Hot spring facilities, public baths, bathing habits at home lead to prevention of COVID-19 and alleviation of symptoms”, “D. Bathing for survivors of COVID-19 is effective for various rehabilitation of patients”. Suitable research approaches for each issue would be required in order to grasp each evidence.

The Effects of Aquatic Walking on the Blood Pressure of Elderly People / 日本温泉気候物理医学会雑誌

  Aquatic walking, which is influenced by the physical characteristics of water such as buoyancy, resistance, water pressure, and water temperature, is known to be effective for reducing stress on joints and increasing muscular strength. However, there is no consensus on its influence on blood pressure changes in elderly people. To address this uncertainty, we researched the effects of aquatic walking on the blood pressure of elderly people. Study participants were 48 females enrolled in a class to prevent the need for nursing care. In accordance with the diagnostic criteria for hypertension, participants were divided into two groups based on initial blood pressure measurements: a “high blood pressure group” with 27 people and a control group with 21 people. Both groups did the following program once a week for five weeks: 10 minute warmup, 15 minutes of aquatic walking (forward, backward, and sideways walking), 10 minute break, and additional 10 minutes of aquatic walking. Systolic blood pressure, diastolic blood pressure, heart rate, and average blood pressure of the participants were recorded. Results showed that the high blood pressure group showed significant decreases in systolic blood pressure after one week, and significant decreases in both diastolic blood pressure and average blood pressure from three weeks onward. No significant change was evident in the control group. However, comparing values measured immediately before and after aquatic walking showed that the control group had a significant post-aquatic walking increase in both systolic and diastolic blood pressures as well as a significant decrease in heart rate. Similar significant post-aquatic walking increases in systolic and diastolic blood pressures as well as a significant decrease in heart rate was also evident in the high blood pressure group from five weeks onward, once their measured values had improved. These results suggest that continuing an aquatic walking program will lower the blood pressure of elderly individuals meeting the diagnostic criteria for hypertension, but it is necessary to be attentive to physical condition because blood pressure increases immediately after aquatic walking in non-hypertensive individuals.

The Effects of Aquatic Walking on the Blood Pressure of Elderly People / 日本温泉気候物理医学会雑誌

  Aquatic walking, which is influenced by the physical characteristics of water such as buoyancy, resistance, water pressure, and water temperature, is known to be effective for reducing stress on joints and increasing muscular strength. However, there is no consensus on its influence on blood pressure changes in elderly people. To address this uncertainty, we researched the effects of aquatic walking on the blood pressure of elderly people. Study participants were 48 females enrolled in a class to prevent the need for nursing care. In accordance with the diagnostic criteria for hypertension, participants were divided into two groups based on initial blood pressure measurements: a “high blood pressure group” with 27 people and a control group with 21 people. Both groups did the following program once a week for five weeks: 10 minute warmup, 15 minutes of aquatic walking (forward, backward, and sideways walking), 10 minute break, and additional 10 minutes of aquatic walking. Systolic blood pressure, diastolic blood pressure, heart rate, and average blood pressure of the participants were recorded. Results showed that the high blood pressure group showed significant decreases in systolic blood pressure after one week, and significant decreases in both diastolic blood pressure and average blood pressure from three weeks onward. No significant change was evident in the control group. However, comparing values measured immediately before and after aquatic walking showed that the control group had a significant post-aquatic walking increase in both systolic and diastolic blood pressures as well as a significant decrease in heart rate. Similar significant post-aquatic walking increases in systolic and diastolic blood pressures as well as a significant decrease in heart rate was also evident in the high blood pressure group from five weeks onward, once their measured values had improved. These results suggest that continuing an aquatic walking program will lower the blood pressure of elderly individuals meeting the diagnostic criteria for hypertension, but it is necessary to be attentive to physical condition because blood pressure increases immediately after aquatic walking in non-hypertensive individuals.

Physiological Effects of Strength Training Incorporating Blood Flow Restriction Underwater / 日本温泉気候物理医学会雑誌

  Strength training performed while restricting blood flow is believed to cause the secretion of growth hormones under low load intensities and allow for muscle hypertrophy and increased muscle strength. This has potential clinical applications for elderly individuals and people with existing conditions. However, previous research has been performed on land, with hemodynamics and growth hormone secretion trends for training performed underwater unclear. Against this background, we investigated the effects of blood flow restriction training underwater on hemodynamics and plasma growth hormone (GH) levels. Twelve healthy university students were divided into two groups: a localized immersion group where only the upper limb of the dominant hand was submerged, and a whole-body immersion group where participants were submerged to the xiphoid process. Immersed according to respective group protocols, both groups performed flexion and extension of the shoulder joint for 10 minutes with a pressurized cuff at the base of the upper arm under both 0 mmHg and 50 mmHg cuff pressures. Measured hemodynamics were heart rate, systolic blood pressure, and diastolic blood pressure. Plasma GH levels were measured from blood samples. This study revealed that underwater blood flow restriction strength training induced plasma GH level secretion under 50 mmHg conditions. In addition, high levels of GH secretion were shown in the localized immersion group for strength training even when the cuff was not pressurized. Conversely, no significant differences were evident in any measured hemodynamic categories. Results suggest that, in addition to cuff pressure, blood flow restriction training is affected by the body part immersed in water.

New insight into Parkinson's disease pathogenesis from reactive oxygen species-mediated extracellular Zn2+ influx.

BACKGROUND: Parkinson's disease (PD) is the common neurodegenerative disorder in the elderly characterized by motor symptoms such as tremors, which is caused by selective loss of nigral dopaminergic neurons. Oxidative stress induced by the auto-oxidation of dopamine has been implicated as a key cause of the selective loss of dopaminergic neurons. METHODS: To understand the selective loss of nigral dopaminergic neurons, the PD pathogenesis is reviewed focused on paraquat (PQ) and 6-hydroxydopamine (6-OHDA)-induced PD in rats. RESULTS: Reactive oxygen species (ROS), which are produced by PQ and 6-OHDA, are retrogradely transported to presynaptic glutamatergic neuron terminals. ROS activate presynaptic transient receptor potential melastatin 2 (TRPM2) cation channels and induce extracellular glutamate accumulation in the substantia nigra pars compacta (SNpc), followed by age-related intracellular Zn2+ dysregulation. Loss of nigral dopaminergic neurons is accelerated by age-related intracellular Zn2+ dysregulation in the SNpc of rat PD models. The intracellular Zn2+ dysregulation in nigral dopaminergic neurons is linked with the rapid influx of extracellular Zn2+ via postsynaptic AMPA receptor activation, suggesting that PQ- and 6-OHDA-induced pathogenesis is linked with age-related intracellular Zn2+ dysregulation in the SNpc. Postsynaptic TRPM2 channels may be also involved in intracellular Zn2+ dysregulation in the SNpc. CONCLUSION: A novel mechanism of nigral dopaminergic degeneration, in which ROS induce rapid intracellular Zn2+ dysregulation, figures out the PD pathogenesis induced by PQ and 6-OHDA in rats. This review deals with new insight into PD pathogenesis from ROS-mediated extracellular Zn2+ influx and its proposed defense strategy.

Physiological Effects of Strength Training Incorporating Blood Flow Restriction Underwater / 日本温泉気候物理医学会雑誌

  Strength training performed while restricting blood flow is believed to cause the secretion of growth hormones under low load intensities and allow for muscle hypertrophy and increased muscle strength. This has potential clinical applications for elderly individuals and people with existing conditions. However, previous research has been performed on land, with hemodynamics and growth hormone secretion trends for training performed underwater unclear. Against this background, we investigated the effects of blood flow restriction training underwater on hemodynamics and plasma growth hormone (GH) levels. Twelve healthy university students were divided into two groups: a localized immersion group where only the upper limb of the dominant hand was submerged, and a whole-body immersion group where participants were submerged to the xiphoid process. Immersed according to respective group protocols, both groups performed flexion and extension of the shoulder joint for 10 minutes with a pressurized cuff at the base of the upper arm under both 0 mmHg and 50 mmHg cuff pressures. Measured hemodynamics were heart rate, systolic blood pressure, and diastolic blood pressure. Plasma GH levels were measured from blood samples. This study revealed that underwater blood flow restriction strength training induced plasma GH level secretion under 50 mmHg conditions. In addition, high levels of GH secretion were shown in the localized immersion group for strength training even when the cuff was not pressurized. Conversely, no significant differences were evident in any measured hemodynamic categories. Results suggest that, in addition to cuff pressure, blood flow restriction training is affected by the body part immersed in water.

Effect of acupuncture at acupoint of Shenshu (BL 23) on the bones of ovariectomized rats.

OBJECTIVE: To investigate the effect of acupuncture at acupoint of Shenshu (BL 23) in ovariectomized rats and sham-operated rats. METHODS: Female Sprague-Dawley rats were divided into the following four groups (n = 12 each): sham operation only (Sham), sham operation with acupuncture (Sham + ACP), ovariectomy only (OVX), and ovariectomy with acupuncture (OVX + ACP). Operations were performed at the 9th week of age. Acupuncture of Shenshu (BL 23) was started at the 11th week of age and conducted 3 times per week until the 26th week of age. RESULTS: Among ovariectomized rats, the acupuncture-treated rats had significantly lower body weights and cross-linked N-telopeptide of type 1 collagen levels in the urine after 3 weeks of acupuncture treatment, higher bone mineral density of the lumbar vertebra after 7 weeks, and smaller trabecular separation of the sixth lumbar vertebra, measured by micro-computed tomography, after 17 weeks than control rats. These effects were not observed in sham-operated rats. Blood concentrations of estradiol were significantly higher in the OVX + ACP group than in the untreated group. Acupuncture treatment increased plasma testosterone levels in sham-operated rats, while this increase was not observed in OVX rats. CONCLUSION: Acupuncture of Shenshu (BL 23) prevents bone loss and structural changes by suppressing bone resorption.

S2-2Carbon dioxide (CO₂) balneotherapy in Germany / 日本温泉気候物理医学会雑誌

  Balneotherapy for humans has a long tradition in Germany. Carbonated water or CO₂ containing spring water has been known for ancient times, not only in spas for bathing but also for drinking. In 1845 the German spa physician Dr. F. Bodo from Bad Nauheim noted a “congested, velvety reddened skin” after taking a bath in warm CO₂ enriched water. Conducting absorption experiments Hediger in 1928 demonstrated for the first time that CO₂ is absorbed into the body by passing through the intact skin. In Germany 80% of the natural mineral spas contain the minimum concentration of 400mg/kg CO₂ required for treatment and 50% of all spas have a CO₂ content higher than 1000 mg/kg which is required for the designation as carbon dioxide enriched water. The spa resorts Bad Nauheim and Bad Krozingen harbor natural mineral springs with the world wide highest CO₂ concentrations containing 2600 mg/kg and 2200 mg/kg, respectively. These springs belong to artesian wells which means the spring water is under a hydrostatic pressure that is high enough to well up to the surface without any pumps. <BR>  The beneficial effects of CO₂ balneotherapy are not known in detail yet. However, animal studies have shown that bathing in carbon dioxide rich water enhances collateral blood flow in ischemic hindlimb through mobilization of endothelial progenitor cells and activation of NO system. Daily CO₂ bathing for 28 days induced a 4 fold increase in collateral vessel density which was prevented by the administration of L-NAME a NO inhibitor. In humans CO₂ bathing improves arteriolar blood flow in patients with arterial occlusive diseases. Patients with necrosis of skin and soft tissue due to disturbed blood flow showed profound improvement of the skin defects with decrease of the necrosis area. To the skin CO₂ enriched water has topical effects. Ten days of rinsing detergent-damaged skin with CO₂ enriched water enhanced clinical skin regeneration, enhanced epidermal lipid synthesis and enhanced barrier repair. Taking together CO₂ balneotherapy has different beneficial effects on human diseases. This review presents the effects of CO₂ enriched water on humans diseases and discusses its clinical indications.

S2-2 Carbon dioxide (CO2) balneotherapy in Germany / 日本温泉気候物理医学会雑誌

  Balneotherapy for humans has a long tradition in Germany. Carbonated water or CO2 containing spring water has been known for ancient times, not only in spas for bathing but also for drinking. In 1845 the German spa physician Dr. F. Bodo from Bad Nauheim noted a “congested, velvety reddened skin” after taking a bath in warm CO2 enriched water. Conducting absorption experiments Hediger in 1928 demonstrated for the first time that CO2 is absorbed into the body by passing through the intact skin. In Germany 80% of the natural mineral spas contain the minimum concentration of 400mg/kg CO2 required for treatment and 50% of all spas have a CO2 content higher than 1000 mg/kg which is required for the designation as carbon dioxide enriched water. The spa resorts Bad Nauheim and Bad Krozingen harbor natural mineral springs with the world wide highest CO2 concentrations containing 2600 mg/kg and 2200 mg/kg, respectively. These springs belong to artesian wells which means the spring water is under a hydrostatic pressure that is high enough to well up to the surface without any pumps.   The beneficial effects of CO2 balneotherapy are not known in detail yet. However, animal studies have shown that bathing in carbon dioxide rich water enhances collateral blood flow in ischemic hindlimb through mobilization of endothelial progenitor cells and activation of NO system. Daily CO2 bathing for 28 days induced a 4 fold increase in collateral vessel density which was prevented by the administration of L-NAME a NO inhibitor. In humans CO2 bathing improves arteriolar blood flow in patients with arterial occlusive diseases. Patients with necrosis of skin and soft tissue due to disturbed blood flow showed profound improvement of the skin defects with decrease of the necrosis area. To the skin CO2 enriched water has topical effects. Ten days of rinsing detergent-damaged skin with CO2 enriched water enhanced clinical skin regeneration, enhanced epidermal lipid synthesis and enhanced barrier repair. Taking together CO2 balneotherapy has different beneficial effects on human diseases. This review presents the effects of CO2 enriched water on humans diseases and discusses its clinical indications.

Positive Healthy Physiological Effects of <I>Shinrin-yoku </I>in Human / 日本温泉気候物理医学会雑誌

  The positive healthy physiological effects of <I>shinrin-yoku </I>in elderly persons were studied. <I>Shinrin-yoku </I>or forest bathing is considered to promote physical relaxation and to have physical and mental health benefits. In this experiment the subjects were elderly 24 male (65.5±2.5years) and 24female (65.0±3.0years) persons who participated in three measurements of <I>shinrin-yoku </I>effects from 2008 to 2010. All the subjects were healthy and volunteered for the experiment. The subjects participated in the <I>shinrin-yoku </I>measurements three times of two hours each on Wednesday in the third week of August in each year. The weather at the time of the three measurements was clear, with temperature of 30°C-32°C, humidity of 58%-60% and wind velocities of 0m/sec-2m/sec. Non-<I>shinrin-yoku </I>measurements were also performed on a different day in an indoor resting environment with the same subjects under the same conditions. For both the <I>shinrin-yoku </I>and non-<I>shinrin-yoku </I>measurements, the subjects were divided into three groups of 8 male and 8 female subjects equally. One was for the visual isolation group in which subjects wore eye masks, another was for the smell isolation group in which subjects wore masks, and the other was the control group in which subjects wore non-isolation material. The concentration of phytoncides in the air was measured using gas chromatography mass spectroscopy. Heart rate (HRs), blood pressure (BP), fasting levels of plasma catecholamine (adrenaline, noradrenalin and dopamine), plasma cortisol and circulating natural killer (NK) cell activity were measured before and after <I>shinrin-yoku</I>. Three kinds of phytoncides derived from trees were detected at the forest-bathing measurement spot in this study. The mean HRs for male subjects under <I>shinrin-yoku </I>and non-shinrin-yoku were 89bpm and 85bpm respectively. The mean HRs for female subjects under <I>shinrin-yoku </I>and non-shinrin-yoku were 86bpm and 85bpm respectively. In the smell isolation group and the control group, systric blood pressure for male and female subjects decreased significantly after <I>shinrin-yoku</I>. In the smell isolation group and the control group, diastolic blood pressure for male subjects decreased significantly after <I>shinrin-yoku</I>. In the smell isolation group and the control group, adrenaline levels for male and female subjects decreased significantly after <I>shinrin-yoku</I>. Among the male under the control and the female under the smell isolation and the control, noradrenaline levels decreased significantly after <I>shinrin-yoku</I>. Similarly, under the smell isolation, and the control, the male and female subjects showed significant decreases in the cortisol level. The NK cell activity of male and female subjects and had no significant change after <I>shinrin-yoku</I>. The BP, catecholamine level, cortisol level, and NK cell activity of male and female subjects showed no significant change after non-<I>shinrin-yoku</I>. The authors believe that this issue, and the general topic of <I>shinrin-yoku </I>and other environments with natural health benefits merit further study. It has been pointed out that the phytoncides and green forest environment in <I>shinrin-yoku </I>have a relaxing effect on the human body. As physical effects of shinrin-yoku, this study of male and female elderly subjects suggested the possibility of physiological effects in which appear within a short time and consist of multiple elements related to the human five senses, including the effects of phytoncides.<BR>  Future issues include accumulation of study results on the linkage between physiological/psychological responses and quantitative/qualitative data on odor and the visual sense.

Positive Healthy Physiological Effects of Shinrin-yoku in Human / 日本温泉気候物理医学会雑誌

  The positive healthy physiological effects of shinrin-yoku in elderly persons were studied. Shinrin-yoku or forest bathing is considered to promote physical relaxation and to have physical and mental health benefits. In this experiment the subjects were elderly 24 male (65.5±2.5years) and 24female (65.0±3.0years) persons who participated in three measurements of shinrin-yoku effects from 2008 to 2010. All the subjects were healthy and volunteered for the experiment. The subjects participated in the shinrin-yoku measurements three times of two hours each on Wednesday in the third week of August in each year. The weather at the time of the three measurements was clear, with temperature of 30°C-32°C, humidity of 58%-60% and wind velocities of 0m/sec-2m/sec. Non-shinrin-yoku measurements were also performed on a different day in an indoor resting environment with the same subjects under the same conditions. For both the shinrin-yoku and non-shinrin-yoku measurements, the subjects were divided into three groups of 8 male and 8 female subjects equally. One was for the visual isolation group in which subjects wore eye masks, another was for the smell isolation group in which subjects wore masks, and the other was the control group in which subjects wore non-isolation material. The concentration of phytoncides in the air was measured using gas chromatography mass spectroscopy. Heart rate (HRs), blood pressure (BP), fasting levels of plasma catecholamine (adrenaline, noradrenalin and dopamine), plasma cortisol and circulating natural killer (NK) cell activity were measured before and after shinrin-yoku. Three kinds of phytoncides derived from trees were detected at the forest-bathing measurement spot in this study. The mean HRs for male subjects under shinrin-yoku and non-shinrin-yoku were 89bpm and 85bpm respectively. The mean HRs for female subjects under shinrin-yoku and non-shinrin-yoku were 86bpm and 85bpm respectively. In the smell isolation group and the control group, systric blood pressure for male and female subjects decreased significantly after shinrin-yoku. In the smell isolation group and the control group, diastolic blood pressure for male subjects decreased significantly after shinrin-yoku. In the smell isolation group and the control group, adrenaline levels for male and female subjects decreased significantly after shinrin-yoku. Among the male under the control and the female under the smell isolation and the control, noradrenaline levels decreased significantly after shinrin-yoku. Similarly, under the smell isolation, and the control, the male and female subjects showed significant decreases in the cortisol level. The NK cell activity of male and female subjects and had no significant change after shinrin-yoku. The BP, catecholamine level, cortisol level, and NK cell activity of male and female subjects showed no significant change after non-shinrin-yoku. The authors believe that this issue, and the general topic of shinrin-yoku and other environments with natural health benefits merit further study. It has been pointed out that the phytoncides and green forest environment in shinrin-yoku have a relaxing effect on the human body. As physical effects of shinrin-yoku, this study of male and female elderly subjects suggested the possibility of physiological effects in which appear within a short time and consist of multiple elements related to the human five senses, including the effects of phytoncides.   Future issues include accumulation of study results on the linkage between physiological/psychological responses and quantitative/qualitative data on odor and the visual sense.

A Physio-Psychological Research on Shinrin-yoku / 日本温泉気候物理医学会雑誌

We performed a physio-psychological research on the mental, physical relaxation and health-keeping effect of <i>Shinrin-yoku</i> (forest walking) in Kawaba village. Eleven male and 8 female healthy elderly residents in Kawaba village, whose average age was 74.0±3.5 years old for male and 74.9±2.9 years old for females volunteered for this experiment. All members walked for one hour in the Kawaba Forest on August 17 under cloudy skies, 30-32°C temperature, 58-60% humidity, and, 0-2m/sec wind condition and walked again for another one hour in a non-forest rural agricultural area on August 21 under almost the same weather conditions. Phytoncides in the air, Profile of Mood State (POMS) test, blood pressure (BP), heart rate (HR), fasting levels of serum natural killer cell activity (NK), plasma catecholamine (adrenaline, noradrenalin and dopamine), plasma cortisol, and serum adiponectin were measured before and after walking. Phytoncides were detected in the forest and non-forest, all members showed a decrease of POMS total scale, BP, adrenalin and serum cortisol. Six (3 male and 3 female subjects) of them expressed an increase of serum NK cell activity after the forest-walking. One female showed a high serum NK cell activity after both forest and non-forest rural walking.<br>Our experiment on the forest-walking in Kawaba village indicated that its relaxation and health-keeping effects, probably due to walking in the fresh forest air.