Wen, Y., Yan, Q., Pan, Y. et al. (2019) Medical empirical research on forest bathing (Shinrin-yoku): a systematic review. Environ Health Prev Med 24, 70

This 2019 study focused on the recent evidence of the relationship between natural environmental exposure through Forest Bathing and human health, and involved a review of 28 papers published between 2015 and 2019.

The results demonstrated that forest bathing activities can have the following effects: 

(1) "remarkably improving" cardiovascular function, blood oxygenation, hormone regulation and function, metabolic activity, immune system function, inflammatory regulation, antioxidant levels, and electrophysiological function; 

(2) "significantly enhancing" people’s emotional state, attitude, and "general feelings towards things"; 

(3) increasing physical and psychological recovery, and adaptive behaviours; 

(4) "obvious alleviation" of anxiety and depression.

The results of this meta-analysis show that Forest Bathing has robust and significant positive effects on a wide variety of key bodily systems and brain functions. The authors conclude that Forest Bathing activities may significantly improve people’s physical and psychological health and contribute greatly to mental and physical resilience. 

Kim, Yunsoo, Yoonhee Choi, and Hyeyun Kim.( 2022) "Positive Effects on Emotional Stress and Sleep Quality of Forest Healing Program for Exhausted Medical Workers during the COVID-19 Outbreak" International Journal of Environmental Research and Public Health 19, no. 5: 3130

In this 2022 study, researchers examined the effect of Forest Bathing on stress levels, exhaustion and sleep quality in healthcare workers who were under extreme workloads during the COVID-19 pandemic. 

From this study, the sleep enhancement and emotional stress reduction effects of forest healing were verified, even in a short schedule of 2 days and 1 night. 

After Nature Immersion, the level of salivary melatonin (the primary hormone responsible for sleep) increased. The results revealed positive effects in terms of relieving insomnia and daytime sleepiness. 

DHEA-S (dehydroepiandrosterone sulfate) is a commonly studied stress marker, and the results of this study showed a significant decrease in DHEA-S levels after the forest healing therapy. The authors note that this reduction was the result of the objective stress improvement due to the forest healing therapy and when clinically interpreted, suggest that experience of stress can be lowered by Nature Immersion, even if the sleep duration is the same or even a little shorter.

The results of this study show that Nature Immersion can be an effective in reducing exhaustion by improving sleep and decreasing daytime sleepiness, and is also effective in reducing stress levels even if sleep levels are sub-optimal. The authors "propose forest healing therapy as one intervention to relieve job stress".

Furuyashiki, A., Tabuchi, K., Norikoshi, K. et al. (2019) A comparative study of the physiological and psychological effects of forest bathing (Shinrin-yoku) on working age people with and without depressive tendencies. Environ Health Prev Med 24, 46 

This 2019 study investigated the physiological and psychological effects of Forest Bathing on working-age individuals in those with depressive tendencies and those without depressive tendencies.

All participants showed significant decreases in blood pressure, tension, anxiety, depression, dejection, anger, hostility, fatigue, and confusion after a forest bathing session. 

After forest bathing, those with depressive tendencies demonstrated significantly greater improvement in many of the mood indicators rather than those without depressive tendencies, and many of the mood indicator results no longer differed between those with and without depressive tendencies.

The drop in blood pressure reported in the present study was the same as in previous studies, and the authors note that this outcome may result from the "physiologically relaxing effect derived from exposure to fragrance from the trees, and the bodily sensations of being in the forest".

The results of this study show that Nature Immersion is effective in reducing anxiety, depression, hostility and fatigue in all individuals, and that these effects are amplified for those experiencing depression or with depressive tendencies which are often associated with chronic stress and burnout. 

Guardini B, Secco L, Moè A, et al. (2023) Three-Day Forest-Bathing Retreat Enhances Positive Affect, Vitality, Optimism, and Gratitude: An Option for Green-Care Tourism in Italy? Forests: 14(7):1423.

Conducted in 2023, this study examined the impact of Forest Bathing on positive affect, vitality, optimism, and gratitude as indicators of hedonic* and eudaimonic** well-being.

The results showed statistically significant increases in participants’ self-reported vitality and gratitude after Forest Bathing compared to the pre-Forest Bathing survey results. 

Data analysis demonstrated that participants’ self-reported optimism increased significantly and emotional response post-intervention shifted toward pleasantness within the valence domain, toward calmness within the arousal domain and toward independence in the dominance domain, as a result of Nature Immersion.

Apathy and disengagement are generally related to feelings of pessimism, disempowerment and hopelessness. This study demonstrates that Nature Immersion can directly remediate these factors by increasing feelings of optimism, gratitude and independence (empowerment). 

* Hedonic: pursuing happiness by engaging in pleasurable experience

** Eudaimonic: pursuing happiness by finding meaning and purpose. Self-fulfillment and self-improvement both contribute to this form of happiness.

Kotera, Y., Richardson, M. & Sheffield, D. (2022) Effects of Shinrin-Yoku (Forest Bathing) and Nature Therapy on Mental Health: a Systematic Review and Meta-analysis. Int J Ment Health Addiction 20, 337–361.

This meta-analysis conducted in 2022 involved the systematic review of 497 research studies and considered the impact of Nature Immersion on various mental health outcomes.

Meta-analysis found that Shinrin-Yoku (Forest Bathing) was reported effective for depression, anxiety, stress and anger in both clinical and non-clinical samples, especially for anxiety. 

The results reported in the selected studies were in line with relevant theories: spending time in nature increased restoration (Bielinis et al. 2019) aligning with Attention Restoration Theory (Kaplan and Kaplan 1989). Stress was reduced through shinrin-yoku (Vujcic et al. 2017; Morita et al. 2007), supporting Stress Reduction Theory (Ulrich et al. 1991). 

The role of nature in affect regulation is often overlooked (Korpela et al. 2018), and although not explicitly explored, findings accord with the three emotion regulatory systems model (threat, drive, and soothing; Richardson et al. 2016); being in nature may activate our soothing system, endorsing compassion, safety and connection, protecting our mental health.

This meta-analysis illustrates the effectiveness of Nature Immersion in the context of leading theories and models. By influencing our experience of drive (motivation), compassion, safety and connection, Nature Immersion in able to counter feelings of apathy, disengagement and disconnection. 

Anna Muro, Albert Feliu-Soler, Josep Canals, et al. (2022) Psychological benefits of Forest Bathing during the COVID-19 pandemic: a pilot study in a Mediterranean forest close to urban areas, Journal of Forest Research, 27(1) 71-75.

In this 2022 study, researchers evaluated changes in psychological affective state and mindfulness after a Forest Bathing session.

Effect sizes observed for all variables were significant and large, with results showing significant increases in positive affect, vigour, friendship and mindfulness, and decreases in negative affect, anxiety, anger, fatigue, tension, and depressive mood.

The results show that Forest Bathing can enhance mental health in terms of overall emotional functioning, as previous studies report in other biomes around the world, and could be employed as a safe and effective technique for mental health prevention and  promotion of psychological wellbeing, decreasing levels of stress, mental fatigue, anxiety, or depressive mood (Chen et al. 2018; Hansen et al. 2017; Kobayashi et al. 2018; Lyu et al. 202 2018; Wen et al. 2019).

The results of this study show the effectiveness of Nature Immersion in treating apathy, disengagement and disconnection by increasing positive thoughts and decreasing depressive mood, increasing feelings of friendship and mindfulness, and decreasing anger.

Chia-Pin (Simon) Yua, Hsuan Hsieh. (2020) Beyond restorative benefits: Evaluating the effect of forest therapy on creativity. Urban Forestry & Urban Greening (51) 126670

Conducted in 2020, this study had three purposes: assessing physiological and psychological responses to Forest Bathing, evaluating the effects of the forest therapy workshop on creativity, and examining the relationship between change in emotions and improvements in creativity.

The results demonstrated that Nature Immersion contributed to participants’ physical and mental health by regulating physiological responses as well as increasing positive emotions and reducing negative emotions. 

In regards to the creativity enhancement, the forest therapy workshop improved participants’ creative performances by 27.74 %, which indicates forest therapy is beneficial for high-level cognitive functioning. 

Moreover, the authors note that the change in creativity correlated significantly and negatively with change in the confusion–bewilderment emotion. This result indicates clarity of thought derived from Nature Immersion contributes to the enhancement of creativity.

The results of this study show the potential of Nature Immersion to reduce negative emotions, increase positive emotions and regulate physiological arousal systems with the effect of increasing clarity of thought, high-level cognitive functioning and creativity. 

Plambech, T., & Konijnendijk van den Bosch, C.C. (2015). The impact of nature on creativity – A study among Danish creative professionals. Urban Forestry & Urban Greening, 14(2), 255- 263

In this 2015 study, researchers investigated the ability of natural environments to enhance creativity among creative professionals.

Findings from this study show that nature does indeed have the capacity to enhance creativity. This study explains how nature has the ability to evoke a creative way of thinking by making us more curious, able to get new ideas as well enabling flexibility in our way of thinking. 

Nature also helps us to recharge our directed-attention which is needed when analyzing and further developing ideas. Nature especially plays a role in the two first phases of a creative process, the Preparation phase and the Incubation phase. 

Natural environments which offer the perceived sensory dimensions ‘Nature’, ‘Space’ and ‘Serene’ seem to be of particular importance for the creative professionals.

The results of this research show that Nature Immersion in natural environments of different kinds, support creative processes by promoting creative and flexible ways of thinking, activating curiosity and restoring directed attention.  

Atchley RA, Strayer DL, Atchley P (2012) Creativity in the Wild: Improving Creative Reasoning through Immersion in Natural Settings. PLoS ONE 7(12): e51474

This study considered the impact of Nature Immersion in contrast to the high cognitive demands of technology rich environments. 

The findings demonstrate that immersion in nature, and the corresponding disconnection from multi-media and technology, increases performance on a creativity, problem-solving task by a full 50%. 

The results demonstrate that there is a cognitive advantage to be realized if we spend time immersed in a natural setting. 

The authors suggest that this advantage comes from an increase in exposure to natural stimuli that are both emotionally positive and low-arousing and a corresponding decrease in exposure to attention demanding technology, which regularly requires that we attend to sudden events, switch amongst tasks, maintain task goals, and inhibit irrelevant actions or cognitions.

This study found exceptionally large increases in creative and problem-solving performance as a result of Nature Immersion. These results demonstrate that the time spent away from demanding technology rich environments during Nature Immersion is itself beneficial to creativity and problem-solving performance, and these benefits are further enhanced by the exposure to positive, low-arousing stimuli found in nature.