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Health Effects of Biogenic Volatile Organic Compounds in the Forest Air

A special issue of International Journal of Environmental Research and Public Health (ISSN 1660-4601). This special issue belongs to the section "Environmental Health".

Deadline for manuscript submissions: closed (28 February 2022) | Viewed by 89253

Special Issue Editors


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Guest Editor
Institute for BioEconomy, National Research Council, 10 Via Madonna del Piano, I-50019 Sesto Fiorentino (FI), Italy
Interests: Bioactive compounds; Energy; Forest bathing; Green extraction; Health; Hydrodynamic cavitation; Pollution; Process yield; Volatile organic compounds
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Institute for BioEconomy, National Research Council, 10 Via Madonna del Piano, I-50019 Sesto Fiorentino (FI), Italy
Interests: Bioactive compounds; Forest bathing; Green extraction; Health; Hydrodynamic cavitation; Pollution; Science communication; Social behavior; Volatile organic compounds
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue intends to cover the emerging field of ecosystem services offered by forests for human health, focusing on biogenic volatile organic compounds (BVOCs), with specific reference to monoterpenes, and will include the following areas: relationships between BVOCs and key physiological health parameters, such as oxidative status, antioxidant/oxidant balance, indicators of the state of the immune system such as natural killer (NK) cells, as well as blood pressure, heart rate variability, salivary cortisol, etc.; relationships among the abovementioned key physiological health parameters and psychological health parameters, such as inferred from the administration of professional questionnaires, and in turn the relationship with BVOCs; dose-dependent responses of the above-mentioned effects; dependence of BVOC chemistry on air quality parameters: formation of secondary organic aerosol (SOA) and countereffects on health; time- and space-distributed mapping of BVOCs and their chemical composition, and relationships with season, meteorological parameters, forest composition, etc.; qualification of sites and hiking trials based on BVOCs concentration and chemical composition; policy recommendations: forest management, maintenance and expansion of valuable hiking trails and shelters, health prescriptions, etc. The expected submissions will be research articles, reviews, and case reports.

Dr. Francesco Meneguzzo
Dr. Federica Zabini
Guest Editors

Manuscript Submission Information

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Keywords

  • air quality
  • biogenic volatile organic compounds
  • forests
  • forest management
  • health
  • hiking trails
  • immune system
  • medical prescriptions
  • monoterpenes

Published Papers (12 papers)

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Research

Jump to: Review, Other

16 pages, 3040 KiB  
Article
Effects of Plant-Emitted Monoterpenes on Anxiety Symptoms: A Propensity-Matched Observational Cohort Study
by Davide Donelli, Francesco Meneguzzo, Michele Antonelli, Diego Ardissino, Giampaolo Niccoli, Giorgio Gronchi, Rita Baraldi, Luisa Neri and Federica Zabini
Int. J. Environ. Res. Public Health 2023, 20(4), 2773; https://doi.org/10.3390/ijerph20042773 - 4 Feb 2023
Cited by 9 | Viewed by 5898
Abstract
Immersive experiences in green areas, particularly in forests, have long been known to produce beneficial effects for human health. However, the exact determinants and mechanisms leading to healthy outcomes remain to be elucidated. The purpose of this observational cohort study was to investigate [...] Read more.
Immersive experiences in green areas, particularly in forests, have long been known to produce beneficial effects for human health. However, the exact determinants and mechanisms leading to healthy outcomes remain to be elucidated. The purpose of this observational cohort study was to investigate whether inhaling plant-emitted biogenic volatile compounds, namely monoterpenes (MTs), can produce specific effects on anxiety symptoms. Data from 505 subjects participating in 39 structured forest therapy sessions at different Italian sites were collected. The air concentration of monoterpenes was measured at each site. STAI state questionnaires were administered before and after the sessions as a measure of anxiety. A propensity score matching analysis was then performed, considering an above-average exposure to inhalable air MTs as the treatment. The estimated effect was −1.28 STAI-S points (95% C.I. −2.51 to −0.06, p = 0.04), indicating that the average effect of exposure to high MT air concentrations during forest therapy sessions was to decrease anxiety symptoms. Full article
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15 pages, 2899 KiB  
Article
Developing Forest Therapy Programmes Based on the Health Benefits of Terpenes in Dominant Tree Species in Tara National Park (Serbia)
by Martina Zorić, Jelena Farkić, Marko Kebert, Emina Mladenović, Dragić Karaklić, Gorana Isailović and Saša Orlović
Int. J. Environ. Res. Public Health 2022, 19(9), 5504; https://doi.org/10.3390/ijerph19095504 - 1 May 2022
Cited by 9 | Viewed by 3191
Abstract
Numerous medical studies have shown the positive effects of forests on different aspects of human health. This study deals with the content of major terpenes in dominant coniferous species in Tara National Park, Serbia, in order to explore the potential for the development [...] Read more.
Numerous medical studies have shown the positive effects of forests on different aspects of human health. This study deals with the content of major terpenes in dominant coniferous species in Tara National Park, Serbia, in order to explore the potential for the development of a novel health tourism programme based on forest therapy. Main terpenes were analysed using a headspace-sampling technique coupled with gas-chromatography-mass spectrometry (Head-space-GC/MS). Needles of fir and spruce growing in the vicinity of hiking trails were investigated for possibilities to perform such therapy. Major detected terpenes were α-cadinol and spathulenol previously described as antiviral, antitumor, antimicrobial and immunomodulatory agents. The results of the study were favourable and worked well with the existing walking infrastructure in the observed area of the Tara Mountain, as they act as invaluable resources for designing the structured forest bathing walks. The study not only adds to the knowledge in the environmental and public health realm but also to tourism and sustainability studies. Full article
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13 pages, 341 KiB  
Article
Health Benefits of the Diverse Volatile Oils in Native Plants of Ancient Ironwood-Giant Cactus Forests of the Sonoran Desert: An Adaptation to Climate Change?
by Gary Paul Nabhan, Eric Daugherty and Tammi Hartung
Int. J. Environ. Res. Public Health 2022, 19(6), 3250; https://doi.org/10.3390/ijerph19063250 - 10 Mar 2022
Cited by 2 | Viewed by 4672
Abstract
We document the species richness and volatile oil diversity in Sonoran Desert plants found in the Arizona Uplands subdivision of this binational USA/Mexico region. Using floristics, we determined that more than 60 species of 178 native plants in the ancient ironwood-giant cactus forests [...] Read more.
We document the species richness and volatile oil diversity in Sonoran Desert plants found in the Arizona Uplands subdivision of this binational USA/Mexico region. Using floristics, we determined that more than 60 species of 178 native plants in the ancient ironwood-giant cactus forests emit fragrant biogenic volatile organic compounds (BVOCs), especially with the onset of summer monsoons. From these desert species, more than 115 volatile oils have been identified from one biogeographic region. For the 5 BVOCs most commonly associated with “forest bathing” practices in Asian temperate forests, at least 15 Sonoran Desert plant species emit them in Arizona Uplands vegetation. We document the potential health benefits attributed to each of 13 BVOCs in isolation, but we also hypothesize that the entire “suite” of BVOCs emitted from a diversity of desert plants during the monsoons may function synergistically to generate additional health benefits. Regular exposure to these BVOC health benefits may become more important to prevent or mitigate diseases of oxidative stress and other climate maladies in a hotter, drier world. Full article
9 pages, 1956 KiB  
Article
The Healing Power of Clean Rivers: In Silico Evaluation of the Antipsoriatic Potential of Apiin and Hyperoside Plant Metabolites Contained in River Waters
by Valentina Roviello, Melinda Gilhen-Baker, Caterina Vicidomini and Giovanni N. Roviello
Int. J. Environ. Res. Public Health 2022, 19(5), 2502; https://doi.org/10.3390/ijerph19052502 - 22 Feb 2022
Cited by 8 | Viewed by 2466
Abstract
Humanity may benefit greatly from intact riverine ecosystems not only because they supply water to be used in the most common human activities, but also for the effects that clean rivers can have on human health. Herein, we used a computational approach to [...] Read more.
Humanity may benefit greatly from intact riverine ecosystems not only because they supply water to be used in the most common human activities, but also for the effects that clean rivers can have on human health. Herein, we used a computational approach to show that some phytochemicals produced by riparian plants as secondary metabolites, which are naturally released into river waters, can have therapeutic properties. These include antipsoriatic activities which we demonstrated in silico by modelling the interaction of apiin, guanosine and hyperoside, a few main river plant metabolites, with NF-kB, IL-17 and IL-36, which are recognized targets involved in psoriasis disease. In particular, we found that apiin and hyperoside are endowed with docking energies and binding affinities which are more favorable than the known reference inhibitors of the three protein targets whilst, in silico, guanosine shows comparable activity with respect to the inhibitors of IL-36 and NF-kB. The low skin permeation (logKp < −8) we predicted for apiin and hyperoside led us to hypothesize their possible utilization as topic antipsoriatic therapeutics, and in particular after PAINS (pan-assay interference compounds) score evaluation, we reached the conclusion that apiin, with no predicted tendency to react nonspecifically with the numerous targets involved in the biological cellular pathways, is particularly interesting for the desired therapeutic application. Full article
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20 pages, 3070 KiB  
Article
Cardiorespiratory Interaction and Autonomic Sleep Quality Improve during Sleep in Beds Made from Pinus cembra (Stone Pine) Solid Wood
by Vincent Grote, Matthias Frühwirth, Helmut K. Lackner, Nandu Goswami, Markus Köstenberger, Rudolf Likar and Maximilian Moser
Int. J. Environ. Res. Public Health 2021, 18(18), 9749; https://doi.org/10.3390/ijerph18189749 - 16 Sep 2021
Cited by 7 | Viewed by 4118
Abstract
Cardiorespiratory interactions (CRIs) reflect the mutual tuning of two important organismic oscillators—the heartbeat and respiration. These interactions can be used as a powerful tool to characterize the self-organizational and recreational quality of sleep. In this randomized, blinded and cross-over design study, we investigated [...] Read more.
Cardiorespiratory interactions (CRIs) reflect the mutual tuning of two important organismic oscillators—the heartbeat and respiration. These interactions can be used as a powerful tool to characterize the self-organizational and recreational quality of sleep. In this randomized, blinded and cross-over design study, we investigated CRIs in 15 subjects over a total of 253 nights who slept in beds made from different materials. One type of bed, used as control, was made of melamine faced chipboard with a wood-like appearance, while the other type was made of solid wood from stone pine (Pinus cembra). We observed a significant increase of vagal activity (measured by respiratory sinus arrhythmia), a decrease in the heart rate (as an indicator of energy consumption during sleep) and an improvement in CRIs, especially during the first hours of sleep in the stone pine beds as compared to the chipboard beds. Subjective assessments of study participants’ well-being in the morning and sub-scalar assessments of their intrapsychic stability were significantly better after they slept in the stone pine bed than after they slept in the chipboard bed. Our observations suggest that CRIs are sensitive to detectable differences in indoor settings that are relevant to human health. Our results are in agreement with those of other studies that have reported that exposure to volatile phytochemical ingredients of stone pine (α-pinene, limonene, bornyl acetate) lead to an improvement in vagal activity and studies that show a reduction in stress parameters upon contact with solid wood surfaces. Full article
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21 pages, 5176 KiB  
Article
Short-Term Effects of Forest Therapy on Mood States: A Pilot Study
by Francesco Meneguzzo, Lorenzo Albanese, Michele Antonelli, Rita Baraldi, Francesco Riccardo Becheri, Francesco Centritto, Davide Donelli, Franco Finelli, Fabio Firenzuoli, Giovanni Margheritini, Valentina Maggini, Sara Nardini, Marta Regina, Federica Zabini and Luisa Neri
Int. J. Environ. Res. Public Health 2021, 18(18), 9509; https://doi.org/10.3390/ijerph18189509 - 9 Sep 2021
Cited by 19 | Viewed by 6407 | Correction
Abstract
Immersion in forest environments was shown to produce beneficial effects to human health, in particular psychophysical relaxation, leading to its growing recognition as a form of integrative medicine. However, limited evidence exists about the statistical significance of the effects and their association with [...] Read more.
Immersion in forest environments was shown to produce beneficial effects to human health, in particular psychophysical relaxation, leading to its growing recognition as a form of integrative medicine. However, limited evidence exists about the statistical significance of the effects and their association with external and environmental variables and personal characteristics. This experimental study aimed to substantiate the very concept of forest therapy by means of the analysis of the significance of its effects on the mood states of anxiety, depression, anger and confusion. Seven forest therapy sessions were performed in remote areas and a control one in an urban park, with participants allowed to attend only one session, resulting in 162 psychological self-assessment questionnaires administered before and after each session. Meteorological comfort, the concentration of volatile organic compounds in the forest atmosphere and environmental coherence were identified as likely important external and environmental variables. Under certain conditions, forest therapy sessions performed in remote sites were shown to outperform the control session, at least for anxiety, anger and confusion. A quantitative analysis of the association of the outcomes with personal sociodemographic characteristics revealed that only sporting habits and age were significantly associated with the outcomes for certain psychological domains. Full article
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19 pages, 4379 KiB  
Article
Forest Bathing Always Makes Sense: Blood Pressure-Lowering and Immune System-Balancing Effects in Late Spring and Winter in Central Europe
by Agnes Peterfalvi, Matyas Meggyes, Lilla Makszin, Nelli Farkas, Eva Miko, Attila Miseta and Laszlo Szereday
Int. J. Environ. Res. Public Health 2021, 18(4), 2067; https://doi.org/10.3390/ijerph18042067 - 20 Feb 2021
Cited by 29 | Viewed by 5810
Abstract
Various formats of forest bathing have been receiving increasing attention owing to their perspectives in health promotion and the treatment of chronic lifestyle diseases. The majority of field studies are still being conducted in the Far Eastern region, and they often make psychological [...] Read more.
Various formats of forest bathing have been receiving increasing attention owing to their perspectives in health promotion and the treatment of chronic lifestyle diseases. The majority of field studies are still being conducted in the Far Eastern region, and they often make psychological assessments mainly in the green season. In our pretest–posttest field experiment, twelve healthy, working-age volunteers participated in a 2-h leisurely forest walking program, first in the green season (May) and then in the winter season (January), in the Mecsek Hills, next to Pécs, Hungary. Systolic blood pressure decreased after the trips both in late spring and in the winter. Based on changes in the expressions of CD69, an early activation marker, NKG2D, a major recognition receptor, perforin, granzyme B, and TIM-3, an inhibitory immune checkpoint molecule, on CD8+ cytotoxic T, NK, NKdim, NKbright, and NKT cells, we detected the stimulation of NKbright cells and activation of all examined immune cell subsets in the green season. In the winter, a slight activating and an interesting balancing effect regarding TIM-3 could be observed considering our finding that basal (pretest) TIM-3 expression by NK cells was significantly lower in the winter. Our work expands the knowledge on and potentials of forest medicine. Full article
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13 pages, 978 KiB  
Article
Comparative Study of the Restorative Effects of Forest and Urban Videos during COVID-19 Lockdown: Intrinsic and Benchmark Values
by Federica Zabini, Lorenzo Albanese, Francesco Riccardo Becheri, Gioele Gavazzi, Fiorenza Giganti, Fabio Giovanelli, Giorgio Gronchi, Andrea Guazzini, Marco Laurino, Qing Li, Tessa Marzi, Francesca Mastorci, Francesco Meneguzzo, Stefania Righi and Maria Pia Viggiano
Int. J. Environ. Res. Public Health 2020, 17(21), 8011; https://doi.org/10.3390/ijerph17218011 - 30 Oct 2020
Cited by 52 | Viewed by 7203
Abstract
The prolonged lockdown imposed to contain the COrona VIrus Disease 19 COVID-19 pandemic prevented many people from direct contact with nature and greenspaces, raising alarms for a possible worsening of mental health. This study investigated the effectiveness of a simple and affordable remedy [...] Read more.
The prolonged lockdown imposed to contain the COrona VIrus Disease 19 COVID-19 pandemic prevented many people from direct contact with nature and greenspaces, raising alarms for a possible worsening of mental health. This study investigated the effectiveness of a simple and affordable remedy for improving psychological well-being, based on audio-visual stimuli brought by a short computer video showing forest environments, with an urban video as a control. Randomly selected participants were assigned the forest or urban video, to look at and listen to early in the morning, and questionnaires to fill out. In particular, the State-Trait Anxiety Inventory (STAI) Form Y collected in baseline condition and at the end of the study and the Part II of the Sheehan Patient Rated Anxiety Scale (SPRAS) collected every day immediately before and after watching the video. The virtual exposure to forest environments showed effective to reduce perceived anxiety levels in people forced by lockdown in limited spaces and environmental deprivation. Although significant, the effects were observed only in the short term, highlighting the limitation of the virtual experiences. The reported effects might also represent a benchmark to disentangle the determinants of health effects due to real forest experiences, for example, the inhalation of biogenic volatile organic compounds (BVOC). Full article
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11 pages, 2957 KiB  
Article
Human Breathable Air in a Mediterranean Forest: Characterization of Monoterpene Concentrations under the Canopy
by Albert Bach, Ana Maria Yáñez-Serrano, Joan Llusià, Iolanda Filella, Roser Maneja and Josep Penuelas
Int. J. Environ. Res. Public Health 2020, 17(12), 4391; https://doi.org/10.3390/ijerph17124391 - 18 Jun 2020
Cited by 19 | Viewed by 6481
Abstract
Monoterpenes have been identified as potential determinants of the human health effects induced by forest exposure. The present study characterizes the total monoterpene concentrations at nose height in a Mediterranean Holm oak forest located in North-East Iberian Peninsula during the annual emission peak [...] Read more.
Monoterpenes have been identified as potential determinants of the human health effects induced by forest exposure. The present study characterizes the total monoterpene concentrations at nose height in a Mediterranean Holm oak forest located in North-East Iberian Peninsula during the annual emission peak (summer and autumn: June to November) using a Proton Transfer Reaction–Mass Spectrometry (PTR-MS). Results show a strong variability of the total monoterpene concentrations in season and daytime. The concentration peak appears during July and August. These two months displayed two average maxima in their diel cycles: One during early morning (from 6:00 to 8:00, 0.30 ppbv for July and 0.41 ppbv for August) and another one at early afternoon (from 13:00 to 15:00, 0.27 ppbv during July and 0.32 ppbv during August). Monoterpene concentrations were strongly related with the temperature (exponentially) and solar radiation (rectangular hyperbolic relationship). The concentrations registered here are similar or higher than in previous ex situ studies showcasing the effects of forests on human health. These findings provide relevant data for the scientific and healthcare community by improving the understanding of monoterpene dynamics at nose height and suggesting further research on the effects of forests on human health, particularly in the Mediterranean region. Full article
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Review

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36 pages, 13848 KiB  
Review
Forest Volatile Organic Compounds and Their Effects on Human Health: A State-of-the-Art Review
by Michele Antonelli, Davide Donelli, Grazia Barbieri, Marco Valussi, Valentina Maggini and Fabio Firenzuoli
Int. J. Environ. Res. Public Health 2020, 17(18), 6506; https://doi.org/10.3390/ijerph17186506 - 7 Sep 2020
Cited by 99 | Viewed by 21152
Abstract
The aim of this research work is to analyze the chemistry and diversity of forest VOCs (volatile organic compounds) and to outline their evidence-based effects on health. This research work was designed as a narrative overview of the scientific literature. Inhaling forest VOCs [...] Read more.
The aim of this research work is to analyze the chemistry and diversity of forest VOCs (volatile organic compounds) and to outline their evidence-based effects on health. This research work was designed as a narrative overview of the scientific literature. Inhaling forest VOCs like limonene and pinene can result in useful antioxidant and anti-inflammatory effects on the airways, and the pharmacological activity of some terpenes absorbed through inhalation may be also beneficial to promote brain functions by decreasing mental fatigue, inducing relaxation, and improving cognitive performance and mood. The tree composition can markedly influence the concentration of specific VOCs in the forest air, which also exhibits cyclic diurnal variations. Moreover, beneficial psychological and physiological effects of visiting a forest cannot be solely attributed to VOC inhalation but are due to a global and integrated stimulation of the five senses, induced by all specific characteristics of the natural environment, with the visual component probably playing a fundamental role in the overall effect. Globally, these findings can have useful implications for individual wellbeing, public health, and landscape design. Further clinical and environmental studies are advised, since the majority of the existing evidence is derived from laboratory findings. Full article
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Other

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48 pages, 1460 KiB  
Systematic Review
Nature Exposure and Its Effects on Immune System Functioning: A Systematic Review
by Liisa Andersen, Sus Sola Corazon and Ulrika Karlsson Stigsdotter
Int. J. Environ. Res. Public Health 2021, 18(4), 1416; https://doi.org/10.3390/ijerph18041416 - 3 Feb 2021
Cited by 55 | Viewed by 17332
Abstract
Given the drastic changes in our lifestyles and ecosystems worldwide, the potential health effects of natural environments have grown into a highly pervasive topic. Recent scientific findings suggest beneficial effects from nature exposure on human immune responses. This review aims at providing a [...] Read more.
Given the drastic changes in our lifestyles and ecosystems worldwide, the potential health effects of natural environments have grown into a highly pervasive topic. Recent scientific findings suggest beneficial effects from nature exposure on human immune responses. This review aims at providing a comprehensive overview of literature published on immunomodulatory effects of nature exposure by inhalation of natural substances. A systematic database search was performed in SCOPUS and PubMed. The quality and potential bias of included studies (n = 33) were assessed by applying the EPHPP (Effective Public Health Practice Project) tool for human studies and the ARRIVE (Animal Research: Reporting of In Vivo Experiments) and SYRCLE (Systematic Review Centre for Laboratory Animal Experimentation) tools for animal studies. The synthesis of reviewed studies points to positive effects of nature exposure on immunological health parameters; such as anti-inflammatory, anti-allergic, anti-asthmatic effects or increased NK (natural killer) cell activity. Decreased expression of pro-inflammatory molecules, infiltration of leukocytes and release of cytotoxic mediators are outcomes that may serve as a baseline for further studies. However, partially weak study designs evoked uncertainties about outcome reproducibility and key questions remain open concerning effect sizes, duration of exposure and contributions of specific vegetation or ecosystem types. Full article
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10 pages, 2896 KiB  
Brief Report
Effects of a Forest Walk on Urinary Dityrosine and Hexanoyl-Lysine in Young People: A Pilot Study
by Ai Yamada, Yoshiko Sato, Tokushi Horike, Masamitsu Miyanaga and Da-Hong Wang
Int. J. Environ. Res. Public Health 2020, 17(14), 4990; https://doi.org/10.3390/ijerph17144990 - 10 Jul 2020
Cited by 4 | Viewed by 2089
Abstract
A few studies indicate exposure to forests may alleviate oxidative stress in the body. However, more evidence is needed to support this potentiality. The purpose of the current study aimed at examining whether there is any difference in urinary levels of oxidatively modified [...] Read more.
A few studies indicate exposure to forests may alleviate oxidative stress in the body. However, more evidence is needed to support this potentiality. The purpose of the current study aimed at examining whether there is any difference in urinary levels of oxidatively modified proteins or lipids—dityrosine (DT) and hexanoyl-lysine (HEL), respectively, after a forest or urban walk. The study was performed on 29 university students who took part in forest walks (Shinjo Village) in Okayama Prefecture of Japan and on 42 university students who took part in urban walks in the downtown area of Okayama City. Urine samples before and after the walks were analyzed for DT and HEL excretion. Air phytoncides during the walks were also measured. We found a decreased tendency in urinary DT and HEL (p < 0.05) in most participants after the forest walks, but not after the urban walks. We further found the total levels of air phytoncides in the forest field were 1.50 times higher compared with those in the urban field. This study suggests the possibility that regular immersion in a forest environment might contribute toward weakening of the oxidative modifications of proteins or lipids in the body. Full article
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