02 Essay
Restorative effects of exposure to greenways : A systematic review
1. Introduction
Urbanization is a prevailing global phenomenon that is experiencing significant growth.
According to forecasts from the United Nations Population Division1, the percentage of urbanization is anticipated to increase, with an estimated 68% of the global population residing in urban areas by 2050. Nevertheless, the process of urbanization has been associated with detrimental impacts on human psychology and physical well-being, resulting in a higher prevalence of depression2 and an elevated susceptibility to obesity and accompanying health complications3. With the increasing severity of these health ailments afflicting contemporary urban populations, there is an urgent need to provide spaces and places for physical and mental health recovery.
Restoration theory is a significant concept in the field of mental health, focusing on the recovery of resources depleted by daily demands. 4 Restorative environments refer to natural
settings that facilitate a transition towards more pleasant emotional states, favorable alterations in physiological activity levels, and improvements in behavior and cognitive functioning5,6
Most of the research on restorative environments has been guided by two theories: the Stress
Recovery Theory (SRT) 7and the Attention Restoration Theory (ART)5. The ART theory explains how natural environments can restore a person's ability to focus their attention voluntarily and effectively by providing effortless fascination and reducing demands on the mechanisms that control attention. The SRT theory suggests that specific visual features in the surroundings might quickly trigger a restoration of psychophysiological well-being by eliciting
INSTRUCTOR: SONG JIALU | DATE: 4/2024-6/2024
pleasant emotional reactions. In 1997, Hartig developed the Perceived Restorativeness Scale (PRS) through four studies to measure the restorative quality of environments 8
Although Attention Restoration Theory (ART) and Stress Reduction Theory (SRT) have provided valuable insights into the restorative benefits of exposure to nature, there is a growing recognition of their limitations. Recent studies have highlighted the need to expand restoration theory and research to fully understand the restorative effects of nature9,10. While there is growing research on the positive impacts of urban green spaces on health promotion and restoration10,11,12, most studies focus on forests, parks, and other vegetation13, with comparatively less attention given to greenways. Greenways, as linear corridors connecting parks, nature reserves, and populated areas, offer unique ecological and social benefits that set them apart from parks 14,15, including serving as wildlife corridors16, providing safe, vehiclefree pathways17, and generating potential tourism revenue. Therefore, expanding restoration theory and research beyond traditional ART and SRT frameworks can help explore the comprehensive array of advantages that exposure to nature can offer.
Because of the rapid development and unique attributes, a separate study is warranted to assess the current level of greenway restoration as well as to provide recommendations for thriving greenway planning. In summary, this study has two main objectives: (1) to analyze and integrate the restorative impacts of greenways on health, behavior, and cognitive function; (2) to provide recommendations for greenway interventions to policymakers, practitioners, and researchers to provide more restorative greenways for people.
2. Method
This systematic review adheres to the PRISMA principles and the search terms refer to reviews in the relevant subject (table2). The literature was searched using online databases (Web of science, Science Direct) during May 2024 using the following search terms. There was no specified deadline for publishing due to a scarcity of literature in the pertinent topic.
Table2. Database search terms
Database Search terms
web of science ((TS=(greenway) OR TS="green trail" OR TS="green way" OR TS=(green corridor)) AND (TS=(restorati*) OR TS=(health) OR TS=(stress recovery) OR TS=(Behavioral) OR TS=(well-being) OR TS=(attention*) OR TS=(mental) OR
TS=(therap*) OR TS=(cognit*) OR TS=(memory) OR TS=(physiological))) NOT (SILOID==("PPRN"))
2.1 review process
Every stage is displayed in Fig1. Three steps make up the review process: title screening, abstract screening, and full text screening. Initially, the Zotero citation manager was used to obtain and manage the database output. 1000 studies in all were included, 3 more were added via snow-balling. Books, book chapters (n=103), reviews (n=19), and retracted papers (n=1) were eliminated along with duplicates (n=80). After reading the abstracts one more time to filter the remaining literature (n = 800), a total of 44 were found to be pertinent to the subject.
Ultimately, 20 documents remained for additional assessment after impertinent articles were excluded after full-text reading(n=24). The inclusion criteria for selecting articles were: (a) the study included empirical results associated with the restoration of cognitive, emotional, behavioral or social resources through nature exposure;(b)the study had been peer-reviewed; (c) the study was published in English;(d)eliminated sources including presentations, posters, book chapters reviews, magazine articles, encyclopedias, and conference proceedings.
sciencedirect
("greenway" OR "green way"OR "green trail") AND ("restoration" OR "restorative"OR "health"OR "wellbeing"OR "Behavioral"OR "stress recovery") AND ("greenway" OR ("green way"OR "green trail") AND ("attention"OR "mental"OR "therapy"OR "cognitive"OR
"MEMORY"OR "physiological")
Table 3 displays the data for every piece of chosen literature that has been registered and examined. This contains the article's publication year, the name(s) of the author(s), the region, sample characteristics (such as age and gender), the study methodology (such as sample size and data collection method), the type of green way (such as natural trail), the type of restorative outcomes (such mental outcomes), data analysis.
1. PRISMA flow diagram selection process
2.3 quality assessment
To examine the quality of the literature, the National Heart, Lung, and Blood Institute (NHLBI) quality evaluation technique was chosen, drawing from a prior systematic review of the restorative consequences of green space9. Several quality assessment guidelines are provided by the assessment tool according to various study designs (e.g. observational cohort, pre-post). Two writers evaluated the quality of the included studies independently using this technique; conversations were held when their conclusions did not align. The percentage of criteria that are met determines the ultimate risk of bias. Reliability is defined as > 75% good, >
50% acceptable, and < 50% poor. The above proportion is based on a prior systematic review9, as the NHLBI does not provide a precise number.
3. Results
Of the 21 articles included, 2 were conducted in the United States, 2 in Canada, 1 in Italy, 2 in Northern Ireland, and 14 in China. (Table3)
There are various types of greenways included, such as mountainous trail, natural trail urban riverside trail, were discussed in these studies. Greenway types were categorised based on the results of previous literature. 14 (1)freeway-to-greenway (2)rail-to-trail (3)waterfront (4)active travel corridor (5)nature trail. Nevertheless, the existing categorization is restricted solely to urban greenways, while encouraging research on greenways in rural locations has been proposed18. Furthermore, the existing classification fails to consider greenways on a broader scope. Various studies, particularly those focused on regional greenways, included several categories of greenways, such as waterfronts and active travel routes. Hence, other from the aforementioned five classifications, this research relies on Little's definition of greenways17, add (6) comprehensive greenway systems or networks that is greenways that are formed by linking different kinds of open areas to greenways in urban and regional scale, into the categories, aside with (7) rural greenways. Many studies looked into the restorative effects of exposure to simulated greenway environment such as soundscapes radio (e.g., bird songs, fountains, etc.) and visual stimuli (e.g., images of natural landscapes). These studies will be labelled as Simulated greenway.
Fig.
Twenty research were divided into one of seven groups based on the sorts of greenways that were previously discussed. However, the included research only addressed four types of greenways. (1) Active travel corridors, or pathways for bicyclists and pedestrians next to or inside of roadways, are the subject of three studies: one from China, one from Canada, and one from the United States. (2) Natural trails are those that wind through undeveloped, preserved areas and have paved or gravel paths suitable for bicyclists, hikers, and/or pedestrians. two studies in total, both from China. (3) Comprehensive greenway networks, or greenways created by connecting various types of open spaces to greenways at the urban and regional levels; China leads the way in this type of greenway, which has the greatest number of articles 11. The other 2 studies were conducted in Northern Ireland. (4) Greenways situated in rural areas are referred to as rural greenways. There is just one Italian article. In the end, we included(5)
Undefined. This type cannot be characterized since it lacks a written or visual description of the greenways that are being researched. There was just one article in all.
Based on previous synthesized studies, the restorative outcome variables were classified in 1 of 5 categories. 9 The first category was cognitive outcomes (registered in 4 papers), including mental processes or functions, such as attention. The second category was emotional outcomes (registered in 3 papers). These outcomes were captured through emotional variables, such as mood or positive emotions, including well-being. The third category was behavioral outcomes (registered in 15 papers) and included variables registering participants’ behaviour mainly physical activity. The fourth category was social outcomes (registered in 2 papers). It included variables registering direct interaction with other people (e.g., social interaction, social capital).
Last, we included a fifth category called complex outcomes (registered in 5 papers). This
category contained variables that fit in multiple categories (e.g., mental health contemplates cognitive, emotional, and behavioural aspects), thus being a multidimensional outcomes category. Table 3 shows the number of studies included in each category classified according to their risk of bias. As some studies examined more than one outcome variable, there are more than 20 entries (a total of 33 entries).
Each study provided a description of the characteristics of their sample. Several studies used samples consisting of individuals who use greenways (35%) or residents of the community (35%). Out of all articles, recruiters were utilized in 20% of them. These recruiters were mostly sourced from the Internet or college students. The research typically utilized simulated reality as the mode of exposure, which made it impractical to enroll actual users. Out of the total number of articles, only 2 (10%) were studies that contained reliable information obtained from VGI. VGI stands for Volunteered Geographic Information.
Regarding data collection, 13 (65 %) studies used the quantitative method such as the rating system or physiological measurement, 1 (5 %) used qualitative methods such as focus group, group interviews, individual interviews, and observations, 4 (20 %) employed the mixedmethods approach. 2 studies (10%) referred to secondary data as an additional source mainly rich volunteered geographic information (VGI) from a self-tracking application was used in studies.
3.1
Greenway exposure
All studies revealed significant associations, except for two. Researchers found that various categories of greenways led to distinct outcomes in terms of restoration. Urban parktype greenways offer the most significant physical and mental restorative advantages, followed by urban river-type greenways. 19
The most common type of greenway in restorative studies is comprehensive greenway systems or networks, which account for 60% of the studies included. The studies included a total of 20 reported outcomes, consisting of 8 behavioral, 4 emotional, 2 social, 2 cognitive, and the other outcomes were classified as complicated. Three outcomes, two behavioral result and one emotional outcome, showed non-significant associations, whereas the remaining outcomes showed substantial relationships.
Out of the researches conducted on the active travel corridor, two of them (66%) focused on physical activity, while only one explored another restorative outcome. All three studies reported substantial results. Three participants in the study were from the United States, China, and Canada. Out of the research conducted on natural trail, two focused on physical activity, and both of them reported significant connections. Both of these researches originated from China.
3.2Outcomes of restoration
3.2.1 Cognitive outcomes
We discovered four findings pertaining to cognitive outcomes, all of which focused on the examination of attention restoration. All of these results were significant, suggesting that
being exposed to greenways had a positive association with cognitive recovery. All the articles that were included were assessed to have an fair rating in quality assessment.
3.2.2 Emotional outcomes
We recorded a grand total of four results regarding the effects of emotional rehabilitation. The primary factors analyzed in this category were positive affect and well-being. Among the four outcomes, three showed a statistically significant positive effect, while one was found to be statistically insignificant. Both items were evaluated to have a fair ranking in quality assessment. Two studies with significant findings examine the mediators between greenway interventions and emotional outcomes. The findings indicate that place attachment, which refers to an individual's relationship, emotions, and purpose toward an environment, as well as environmental stressors like air pollution, garbage, and traffic noise, are important mediators.
20,21
3.2.3 Behavioral outcomes
There were a total of 12 investigations conducted on this particular variable. We observed a total of 14 outcomes pertaining to the impact of behavioral recovery. Out of them, there were 12 notable results and only two detected effects were found to be insignificant. The variable most frequently examined in this category was physical activity. The other two studies focused on health-promoting behavior compared to healthy travel, one study examined moderate-tovigorous physical activity, and one study explored sedentary behavior. Out of the 12 studies, nine were assessed to have a good or fair accessing ranking. After excluding the three studies
that were determined to have a poor quality, all of the remaining studies yielded meaningful results.
Significant results show that greenway interventions can be successful in promoting physical activity22(includes walking time25, moderate-to-vigorous physical activity23), physical activity diversity24 while reducing sedentary behavior25. However, the effects are restricted to distance 23,25,26 and destinations(when individuals utilize greenways as travel routes)22
3.2.4
Social outcomes
Out of the 20 studies that were chosen, 2 social outcomes were recorded, and both of them were found to be statistically significant. The results encompassed social capital and social interaction. Both trials had an fair ranking. There were mixed findings for social capital. The research conducted by Hunter et al. demonstrated a marginal enhancement in local aera trust, as well as a slight decline in social networks, such as contact with friends, family, and neighbors. 27
3.2.5. Complicated outcomes
We have defined six outcomes, which cover many components within a broader notion. For example, mental health has cognitive, affective, and behavioral aspects, making it applicable to more than one category. Statistically significant effects were observed in seven instances. The variables most frequently examined in this category were quality of life and mental health. All the publications included in the study were assessed to be fair in rank.
However, a clear distance-decay effect of this intervention was demonstrated in the study. One
study point out that large-scale greenway mainly promoted the mental health of residents living within 2 km of the greenway.28
3.3 Quality Assessment
The quality assessment process (Tables 4, 5, and 6) show that 2 studies were categorized as being of good quality, 15 studies were categorized as being of fair quality, and 3 studies were categorized as being of poor quality. Twenty papers yielded a total of thirty results. After excluding results from the studies rated as poor quality, there were 24 significant results (previously 27) and 2 non-significant results (previously 3). The results suggest that greenways have a positive impact on restoration.
4. Discussion
This literature examines studies conducted in various global areas that investigate the restorative effects of greenways and the factors that impact these effects. The main objective is to thoroughly investigate the distinct regenerative effects of greenways and the related limitations. Another objective is to offer greenway planners suggestions for enhancing the restorative results of greenways.
This systematic review is conducted on a sample of 20 papers with diverse study designs.
The review identifies five distinct types of outcomes (cognitive, emotional, behavioral, social, and complex outcomes) that result from exposure to greenways for restorativeness. Based on a prior analysis of research regarding the advantages of being in natural environments, it has been found that green spaces have a restorative effect29,30. Additionally, there are numerous
aspects that can impact the outcomes of this restorative experience.31–33 Our research contributes to this finding by demonstrating the positive effects that greenways, a distinct type of linear green space, have on restoration, as well as the elements that determine these effects.
Our findings indicate that greenways have a variety of restorative advantages. In addition, all studies found no significant adverse effects of greenway exposure on restorative results. Only three research reported insignificant effects. 18,27 Specifically, West & Shores et al. (2015) found that there was no significant relationship between greenways and physical activity (walking, moderate activity, or vigorous activity)18. According to previous reports, certain characteristics of green spaces may be negatively restorative for people. 34 However, the insignificant results reported in this study could also be due to a loophole in the experimental setup, which was also mentioned by the researcher. The trial was done at a temperature below the reported average, despite previous research discovered that physical activity can be influenced greatly by weather.35 In addition, the length of the greenway in this study was less than 2 miles, whereas previous studies have pointed out the size that greenways need to reach in order to be of greater use.
The other research found that the greenway intervention did not influence physical activity. 27It is probable that because the research began examining the greenway six months after its completion, the investigation was too early to detect changes in population levels. A significant body of research indicates that studies conducted over longer periods of time are necessary to establish the enduring impacts of green spaces on individuals.12
Subsequent studies are suggested to determine a reasonable greenway length and conduct the study in appropriate weather. There are no present studies that quantify the size of greenways needed to have an restorative impact, but most of the studies have been conducted on greenway lengths greater than 4 miles. For the weather in which the study was conducted, previous studies have shown that the number of activities in the green space peaks at 84 °F and begins to decrease at a rate of 0.045 counts for every 1 °F increase in temperature above 84 °F.
Additionally, there was one study suggest that there is no intervention effect on the improvement of mental wellbeing.27 The authors propose that this phenomenon could be attributed to the relatively brief interval between the assessment and the conclusion of construction (the assessment commenced 6 months after construction was finished), an argument that is reasonable. This is due to the fact that, out of the 20 research, excluding the
3 virtual situations and the 10 articles that did not define the duration of the intervention, 9
out of the remaining 10 articles had an intervention period exceeding 6 months and shown significant outcomes. The full extent of the public health benefits of urban greenways may require a longer time to become apparent. Therefore, when investigating the beneficial results of greenways, it is advisable to choose subjects that have been fully constructed for an extended duration. It is necessary to enhance the evaluation methods in order to accurately measure the intricate nature of urban restorativeness.
Out of the 20 articles, only 3 demonstrated a link that was not statistically significant, and no detrimental consequences were observed in any of the investigations. Given the limited
number of greenway restorative studies, it is important for future research to investigate whether our findings are an anomaly. Greenways may have a detrimental impact on restorativeness. Research has demonstrated that both human and traffic noise have a detrimental effect on mental rejuvenation20,36, which is a major drawback of greenways. This is likely because greenways, being linear pathways with driveways and sparse vegetation, do not effectively block the noise from passing vehicles. Additionally, certain types of greenways, such as active travel corridors, are located next to roads and therefore inevitably expose users to road noise. Greenways that include many adverse aspects have the potential to become hazardous and perilous areas within a community.
Our findings also show that the majority of greenway restoration research has focused on comprehensive greenway systems or networks, accounting for 60% of the papers reviewed. This makes sense given that greenways of a certain size often have a variety of topologies. Furthermore, while examining the restorative impacts of different greenways, researchers discovered that different categories of greenways yielded varying outcomes in terms of restorativeness. Urban park-type greenways provide the most substantial physical and mental restorative benefits, with urban river-type greenways ranking second. 19 This illustrates that the most advantageous approach for restoring greenways is to develop park-like greenways and incorporate water elements, provided that the circumstances permit. However, the lack of uniform criteria for categorizing greenways prevented the standardization of restorability assessments across various types. It is advisable for future studies to strive for a consistent classification criterion for greenways.
Few studies examine the restorative experience of this active perspective. Out of 20 studies, only one considered the traveller’s movement, applying virtual scenarios simulating bikers moving along a greenway at 25 km/h. Greenways are often used for cycling.37and studies have shown that that roadside configurations have an effect on driver behaviour.38 It is recommended that restorative experiences through motion be promoted, especially in travel active greenways, such as active transportation corridors, due to the nature of this activity.
In summary, the greenway has a beneficial effect on restorativeness. This is in line with prior research results.29 However, multiple research have demonstrated a clear distancedecay effect of this intervention. 25,28 This systematic review encourages the application of these findings to other forms of policy, such as revamping and retrofitting greenways to promote people's restorative activities and improve their benefits. By advocating for such legislation, entire communities can reap the advantages of engaging with greenways and experiencing their restorative impacts.
The literature on greenways is broad, but there are fewer publications addressing restorative research, and only 20 were selected for this analysis, therefore the systematic review's results may be skewed. Furthermore, due to the adoption of a comprehensive understanding of restorativeness, the studies included in the analysis naturally differed significantly in terms of their study design, population and data analysis. This variation may have resulted in increased diversity of outcomes, thus impacting the conclusions drawn from the systematic review. In addition, despite the utilization of a standardized quality assessment method to categorize and appraise various study designs, there remains a certain level of
subjectivity in the evaluation process. Moreover, this review exclusively focused on English literature, thus disregarding relevant research conducted in other languages, thereby introducing potential bias into the conclusions.
5.Conclusion
Current information on the impacts of being exposed to greenway environments on cognitive, emotional, social, and behavioral well-being. In summary, our findings indicate that being exposed to greenways has a diverse restorativeimpact. Additionally, we have observed a scarcity of studies that compare the restorative benefits of exposure to different types of greenways. Furthermore, there is a dearth of research on the enduring impacts of greenway exposure on restorative outcomes.Enhancing scientific knowledge and formulating precise instructions for health practitionersand policy makers necessitates a more profound comprehension of these traits.
1. Was the study question or objective clearly stated?
2. Was the study population clearly and fully described, including a case definition? yY 3. Were the cases consecutive?YY 4. Were the subjects comparable?YY 5. Was the intervention clearly described?YY 6. Were the outcome measures clearly defined, valid, reliable, and implemented consistentl y across all stud y p artici p ants?
7. Was the length of follow-up adequate?NAY 8. Were the statistical methods welldescribed?
9. Were the results well-described?YY accessing qualityGG
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1. Was the study question or objective clearly stated?Y 2. Were eligibility/selection criteria for the study population prespecified and clearly described? Y 3. Were the participants in the study representative of those who would be eligible for the test/service/intervention in the g eneral or clinical N 4. Were all eligible participants that met the prespecified entry criteria enrolled? Y 5. Was the sample size sufficiently large to provide confidence in the findings?
6. Was the test/service/intervention clearly described and delivered consistently across the study population? Y 7. Were the outcome measures prespecified, clearly defined, valid, reliable, and assessed consistently across all stud y p artici p ants? Y 8. Were the people assessing the outcomes blinded to the participants' exposures/interventions?
9. Was the loss to follow-up after baseline 20% or less? Were those lost to follow-up accounted for in the anal y sis?
10. Did the statistical methods examine changes in outcome measures from before to after the intervention? Were statistical tests done that provided p values for the pre-to-post changes?
11. Were outcome measures of interest taken multiple times before the intervention and multiple times after the intervention (i.e., did they use an interrupted timeseries design)?
12. If the intervention was conducted at a group level (e.g., a whole hospital, a community, etc.) did the statistical analysis take into account the use of individual-level data to determine effects at the group level?
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