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Trends in research related to “Shinrin-yoku” (taking in the forest atmosphere or forest bathing) in Japan

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"Shinrin-yoku", which can be defined as "taking in the forest atmosphere or forest bathing", has been receiving increasing attention in Japan in recent years for its capacity to provide relaxation and reduce stress. Since 2004, the authors of this paper have been involved in an investigation designed to ascertain the physiological effects of "Shinrin-yoku" within the framework of the "Therapeutic Effects of Forests" project. We have conducted physiological experiments, both in actual forests and in the laboratory, to elucidate the physiological effects on individuals of exposure to the total environment of forests or to only certain elements of this environment, such as the odor of wood, the sound of running stream water, and the scenery of the forest. We have obtained physiological measurements of central nervous activity, autonomic nervous activity, and biomarkers reflecting stress response that can be applied in this line of approach. Using these measurements, we have summarized the separate elements of forests in terms of the five senses. We have also reviewed a selection of field studies and introduced a number of results from ongoing projects as well as those from early studies. Future perspectives are also discussed.
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... Previous studies indicated that subjects in a forest environment had more enhanced parasympathetic and lower sympathetic nervous activity than those in an urban environment [15,27]. HRV analysis is thus a useful method for detecting the sympathetic and parasympathetic nervous activity separately on a minute-by-minute basis [51]. Sympathetic nervous activity can also be determined by measuring the levels of urinary adrenaline and/or noradrenaline [48], and there are significant correlations between blood pressure and urinary adrenaline and noradrenaline levels [49]. ...
... This indicated that higher activity of the sympathetic nervous system was a very important risk factor for cardiovascular diseases [52]. On the other hand, it has been reported that forest bathing/shinrin-yoku reduced sympathetic nervous activity, increased parasympathetic nervous activity, and regulated the balance of autonomic nerves [9,[15][16][17]51]. As a result, forest environments reduced blood pressure and heart rate ( Table 2) and had relaxing effects [15][16][17]51]. ...
... On the other hand, it has been reported that forest bathing/shinrin-yoku reduced sympathetic nervous activity, increased parasympathetic nervous activity, and regulated the balance of autonomic nerves [9,[15][16][17]51]. As a result, forest environments reduced blood pressure and heart rate ( Table 2) and had relaxing effects [15][16][17]51]. Table 2. Forest bathing/shinrin-yoku significantly decreased the pulse rate in male subjects. ...
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Cardiovascular diseases (CVDs) are a group of disorders of the heart and blood vessels and include coronary heart disease, cerebrovascular disease, rheumatic heart disease, and other conditions, which are leading causes of global morbidity and mortality. It is very important to establish preventive measures against CVDs, including hypertension. Against this background, forest bathing/shinrin-yoku is attracting attention as a new method of health promotion and disease prevention. Forest bathing/shinrin-yoku is an activity that utilizes the healing effects of forests to promote people’s health and prevent disease by stimulating the five senses, including sight, smell, hearing, taste, and touch, through forest visits. Since 2004, many scientific studies on the psychological and physiological effects of forest bathing/shinrin-yoku have been conducted, and many original scientific articles have been published. It has been reported that forest bathing/shinrin-yoku boosted immune system by increasing human natural killer activity and anticancer proteins in natural killer, lowered blood pressure and pulse rate, reduced stress hormones including adrenaline, noradrenaline in urine and cortisol in serum and saliva, increased the parasympathetic nervous activity and decreased the sympathetic nervous activity, improved sleep, reduced the negative emotions and increased positive feelings. In this article, the author reviewed the preventive effects of forest bathing/shinrin-yoku on CVDs from the perspectives of the effects of forest bathing/shinrin-yoku on stress hormones, parasympathetic nervous and sympathetic nervous systems, sleep, blood pressure and heart/pulse rate, and other mechanisms based on the published scientific evidence.
... Its responses reflect psychological factors like emotions, motivation, attention, preferences, and physical movement, primarily managed by the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS) [60]. Common ANS indicators include blood pressure (SBP, DBP), pulse rate (P) [61], oxygenated hemoglobin concentration in the prefrontal cortex (oxy-Hb) [62], heart rate variability (HRV) [59,62,63], flow-mediated dilation (FMD) [20,62], skin conductance (SC), and skin temperature (ST). The CNS, comprising the spinal cord and brain, is crucial for human behavioral patterns and sensory functions, including hearing, taste, smell, sensation, and sight. ...
... It also controls fine motor skills, particularly in the hands, feet, and face [64,65]. Measures related to the CNS include electroencephalography (EEG) recordings for brainwave analysis [66], cerebral blood flow dynamics assessed through changes in hemoglobin concentration [63], brain region activation via functional magnetic resonance imaging (fMRI) or near-infrared spectroscopy (NIRS) [46,[67][68][69], and electromyography (EMG) for muscle activity analysis [70]. Biomarkers commonly studied in the context of human-environment interactions include salivary alpha-amylase activity [71], salivary cortisol concentration [63], and salivary secretory immunoglobulin A (IgA) levels [63]. ...
... Measures related to the CNS include electroencephalography (EEG) recordings for brainwave analysis [66], cerebral blood flow dynamics assessed through changes in hemoglobin concentration [63], brain region activation via functional magnetic resonance imaging (fMRI) or near-infrared spectroscopy (NIRS) [46,[67][68][69], and electromyography (EMG) for muscle activity analysis [70]. Biomarkers commonly studied in the context of human-environment interactions include salivary alpha-amylase activity [71], salivary cortisol concentration [63], and salivary secretory immunoglobulin A (IgA) levels [63]. ...
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The smellscape of garden plants plays a crucial role in promoting human well-being. Despite this, empirical data on the specific effects of distinct stimulation methods on public health remain insufficient. The objective of this research is to investigate the influence of three distinct sensory modalities, olfactory, visual, and their combined effect, on both physiological and psychological reactions to a pine forest’s smellscape. A sample of 95 college students was selected, with data collected through both physiological and psychological measurements. The analysis focused on variables such as blood pressure (BP), pulse rate (P), pulse pressure (PP), skin conductance (SC), brainwave patterns (α, β), the odor emotion semantic differential (SD), and the State Anxiety Inventory (S-AI) scale. The results reveal that in the pine forest aroma environment, the central nervous system shows a compromise effect during olfactory–visual interaction, with greater autonomic nervous system (ANS) activation compared with either stimulus alone, suggesting cumulative effects. Psychologically, the influence of olfactory interaction on anxiety fell between that of visual and olfactory stimulation. Participants consistently reported that the combination of both the sight and scent of a pine forest was the most invigorating. Furthermore, research revealed that combining olfactory and visual stimuli led to a more profound amplification of positive environmental perceptions compared with when each sense was engaged individually. These findings lay the groundwork for understanding how garden plant aromas contribute to human well-being.
... Nature supports health through food, water, and materials and provides nonmaterial health benefits such as recreation, leisure activities, personal development, socialization, and beauty (Huynh et al., 2022). Natural environments also support cardiovascular health, reducing inflammatory stress, regulating the sympathetic nervous system, and improving sleep quality (Bahman et al., 2014;Cutshall et al., 2011;Marselle et al., 2014;Morita et al., 2011;Park et al., 2010;Song et al., 2019;Tsunetsugu et al., 2010;Tsutsumi et al., 2017). Nature's nourishing relationships can be expressed through perceived interconnectedness with self, others, and the spiritual world through deep meanings embraced by Indigenous Peoples worldwide, creating a powerful sense of identity, place, and heritage that cannot be achieved by alternative methods (Auer et al., 2017;Salmón, 2000). ...
... Thus, forest environments offer various mental and physical health benefits, including alleviating anxiety and depression [5], relieving stress [10,15,16], relieving inflammation [6,17], enhancing immune function [18,19], and preventing cardiovascular disease [6,20,21]. They also provide spaces for rest and recreation [22]. ...
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Background and objectives: Forest environments provide various healing benefits for humans and have been widely studied. Nevertheless, the field of forest management for forest healing remains relatively understudied. The purpose of this study is to utilize thermal environmental simulation to derive forest management scenarios that are optimized for forest healing. Methods: This study focused on the Seogwipo Experimental Forest on Jeju Island, Korea. Three-dimensional forest models were generated based on field surveys. Thermal environment simulations were conducted using Grasshopper with the Ladybug and Honeybee plug-ins, and the thermal comfort levels of six forest management scenarios were evaluated using the Universal Thermal Climate Index (UTCI). Results: The simulation results showed that, among all the scenarios, only scenario (c), “10% thinning in the buffer zone”, led to an improvement in thermal comfort. Additionally, the study identified discrepancies in thermal comfort between different forest management scenarios. Conclusions: In the management of forests for healing forestry purposes, the distinction of forest zones by use and the application of different forest management scenarios have thermal comfort implications. Thus, the methodology could be employed in forest management for forest healing purposes.
... In addition, many studies have reported that forest visits and forest walks significantly decrease sympathetic nervous system activity and increase parasympathetic nervous system activity compared to the same activities in an urban environment. Shinrin-Yoku lowers blood pressure by inhibiting the renin-angiotensin system (37). Research has also shown that practising Shinrin-Yoku increases the adiponectin level in the serum. ...
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The term ‘Forest therapy’ covers both preventive and therapeutic interventions in the forest. It is increasingly used for health promotive activities that are also referred to in the literature as “Forest bathing” (jap. “Shinrin-Yoku”), forest walks, and forest healing as well as for therapeutic purposes like nature therapy. It involves consciously engaging in slow, multi-sensory, immersive experiences in forests and other natural and semi-natural environments to achieve mental and physical health and well-being. There is a growing body of evidence-based research demonstrating the physiological and psychological effects of forests on health. Physiological effects can be seen in improvements in blood pressure, heart rate, cortisol levels, pain relief, stress reduction, respiratory function, and general wellbeing. It has been confirmed to have psychological effects on symptoms of depression, and anxiety, improving quality of life, mood, emotional and physical burnout, self-perception and acceptance, concentration, and improving cognitive function. Shinrin-Yoku leads to a deepening of the relationship between man and nature, and to the ‘invisible’ world. Mindfulness in and with nature, on the other hand, is a new setting that involves the ability to observe both one’s perceptions and those of nature in an open and non-judgmental experience. Research has shown that mindfulness indoors reduces symptoms of depression and anxiety, significantly reduces overall stress, and improves quality of life. This type of intervention has been shown to help improve chronic physical conditions, including cardiovascular and malignant diseases. The European Society of Hypertension has recognized the benefits of mindfulness and included it as a supportive, i.e., non-pharmacological therapy in the treatment guidelines for arterial hypertension in 2023. In this paper, the researchers argue using both methods in a combined outdoor setting as a comprehensive approach to lay the foundations for social prescribing to support usual healthcare, to improve health outcomes.
... For example, the visual connection with nature could lower blood pressure and heart rate [2] and positively impact attitude and overall happiness [3]. In addition, the non-visual connection with nature could reduce systolic blood pressure and stress hormones [4,5] and result in perceived improvements in mental health and tranquility [6,7]. Yale social ecologist Stephen Kellert proposed the three-dimensional framework for biophilic design, suggesting that "human satisfaction and wellbeing continue to be reliant on perceiving and responding to sensory variability, especially when this occurs in structured and organized ways within the built environment" [8]. ...
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Biophilic design introduces a variety of sensory elements into the built environment, incorporating a natural experience into daily life. From the environmental psychology aspect, the effects of multisensory stimulus are not a result of simply adding the effects of uni-sensory stimuli, and the interactive effects among sensory approaches need to be considered. With the demand for promoting health and well-being, increasing numbers of studies began to investigate sensory systems other than just the visual cue of the biophilic design. This review focuses on the multisensory effect of biophilic design on human psychological and physiological responses as well as cognitive function. We summarized empirical evidence of the interactions between two and three sensory modalities from existing research. In addition, we systematically summarized the key methods and technologies used in experimental studies that explore the health benefits of biophilic design in terms of study types and population, environmental exposure simulation, health benefit measurement, and experimental process design. We finally identified some knowledge gaps in and future directions for biophilic design studies from the multisensory interaction perspective. The experimental design of quantifying the effects of multisensory interaction and its lasting effects are the focus of future research.
... Forest bathing has been widely promoted over the last two decades, particularly in high-income countries such as Japan, the United States, China, South Korea, the United Kingdom, Finland, and Canada [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Forest bathing, also known as Shinrin-yoku, is the practice of immersing oneself in the environment of a forest to enhance one's physical and mental health [19][20][21][22][23][24][25]. Forest bathing encourages connecting with nature and taking in the forest's environment to improve physical and mental wellbeing [16][17][26][27]. ...
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Park therapy can improve mental health and reduce stress levels. We investigated how walking in and viewing autumn forests affected people's physiological and psychological responses. The experiments were carried out on one walking route to one viewing point in urban park and city street and involved 20 adults. Blood pressure and heart rate were monitored to evaluate physiological effects, while the Profile of Mood States and the State-Trait Anxiety Inventory were employed to assess psychological effects. Walking along the edge of an autumn forest may have resulted in a lower heart rate and systolic blood pressure than walking in the city street. The average heart rate of Japanese adults was significantly lower than that of Indonesians. All negative mood states were lower; vigor was higher after viewing autumn forests in Indonesians than in Japanese. Confusion, tension, and total mood disturbance were lower in Japanese than in Indonesians after viewing the autumn forest. The anxiety level was lower after walking among Indonesians and viewing the autumn forest among all adults. Finally, walking in and viewing autumn forests in an urban park leads to physiological and psychological relaxation.
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The Azorean Cryptomeria japonica forest operations and wood industry generate considerable foliage biomass residues that are used for local essential oil (EO) production. However, research on seasonal variation of C. japonica EO remains scarce. In this study, the EOs from fresh Azorean C. japonica foliage (Az–CJF) collected in autumn (Aut) and spring (Spr) were obtained via hydrodistillation and investigated for their physical properties, yield, chemical composition, and bioactivities. Both EOs presented a strong odor, a yellowish color, a density around 0.9 g·mL−1, and similar yields (approximately 1% v/w, dry matter). Nevertheless, the GC–MS analyses showed a decrease in monoterpene hydrocarbons (MH) and an increase in oxygenated sesquiterpenes (OS) contents in Spr–EO compared with Aut–EO (16% vs. 35% for MH and 45% vs. 31% for OS, respectively). In addition, the predominant components were kaur-16-ene (23%) for Spr–EO and phyllocladene (19%) for Aut–EO, revealing that both EOs were rich in diterpene hydrocarbons (29% vs. 26%). Concerning its toxicity against brine shrimp, a low mortality (0–38%) was observed at a concentration range of 100–180 μg·mL−1. Regarding the anti-cholinesterase properties, both EOs were inactive against acetylcholinesterase but showed anti-butyrylcholinesterase activity superior to (–)-α-pinene, a major compound of Az–CJF EO (IC50 values: 84, 148, and 648 μg·mL−1 for Spr–EO, Aut–EO, and α-pinene, respectively). Overall, the results indicate the potential benefit of both seasonal EOs in Alzheimer’s disease treatment. In conclusion, this study demonstrated that season strongly influences the Az–CJF EO quantitative composition and thus its bioactivity, aiding in the selection of the most high-quality raw materials for use in Azorean C. japonica EO aromatherapy industry.
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In order to make the space design of a comfortable bathing in the forest atmosphere (BIFA), it is important to investigate the effect to a human body first and then the characters of many physical factors constituting the forest space. In this paper we research and analyze physical factors constituting the elements of BIFA, especially light intensity and thermal effect. To make clear the effect of BIFA, this experiment was done in the forest [Seiwa Residents' Woodland] and the city [Chiba City] respectively at the same time. The subjects of this experiment are twelve, and the results were recorded by rating to some evaluation scales, and data are compared from the viewpoint of comfortableness. From this result, we can clearly notice psychological and physiological effects at the case of forest. In the mountainside of a village in summer under the fine sky, the values of the light intensity were subjectively seemed to be the same as in the city though the real intensity was 1/22 of the city. Moreover, at the case of thermal effect, we surely understand that it is cooler and more comfortable in the forest than in the city from the resulting data through the whole day.
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