Green Spaces

Jacob Schor ND

July 20, 2009

 

For the last four years I’ve been taking our dog Poppy to Cherry Creek State Park several times a week to walk in the ‘off leash’ area.  This area is located on the south end of the park and is accessed from a parking lot by the group picnic area by a dirt road that leads past the wetland wildlife preserve and then parallels the creek over toward the horse corrals.  Initially we would go to give the dog a chance to run off leash, socialize with other dogs and swim in the creek.  It gave me pleasure to see her smile.  Over the years I’ve come to take great pleasure myself in walking through these grasslands and watching the daily changes in the plants and river as they move through their yearly cycles.  This year especially with the extra rain, everything is so much more intense, everything more lush, the flowers larger, the grasses taller.  We are coming into the season now where the grasses and go to seed and already many have turned to gold and transformed almost magically.  Other plants have also reached their seasonal peak, flowers are starting to wilt, the bright greens of early summer take on hues that warn of fall. 

Historically the phrase, ‘healing power of nature’ dates back to the school of Hippocrates in ancient Greece and refers not so much to the nature outside in the world but to the inner nature of the body.  For centuries a debate has waged among the schools of medicine as to how much to rely on this inner healer.  Those following the Hippocratic school have favored a hands off approach, let nature heal.  The followers of Galen have advocated a more active role, a kind of physician as fixer, in contrast to the Hippocratic image of physician as observer or at most helper to nature.

There is another meaning, perhaps even a more commonly used one, to the phrase, ‘healing power of nature. ’ People often use it to refer to the health benefits derived from exposure to the natural world.  I’ve written in the past of the Japanese practice of  “Woods walking.” They call it Shinrin-yoku and research suggests it has both a physiological and psychological benefits.

http://denvernaturopathic.com/news/woodwalking.html

There is little debate any longer that green spaces within urban areas produce health benefits for those who use them.  An interesting paper caught my eye recently that presented the health benefits from green spaces in an interesting light.

We need to divert this conversation momentarily to what are called the Determinants of Health.  Starting in the 1970s with the research by McKeown and followed by Health Canada’s LaLonde Report, a great deal of attention has been focused on identifying the factors that most predict or determine whether people will be healthy or not.  The results of these efforts are worth considering during the current debates on health care.  For most of the world’s population access to health care plays a relatively minor role in their health and longevity.  

Health Canada’s webpage describing the Determinants of Health:

http://www.phac-aspc.gc.ca/ph-sp/determinants/index-eng.php

The most important determinant of health is income.  Rich people live longer than poor people.  Though this sounds simple enough to explain, but in fact it isn’t just that rich people have more money to buy better housing, food, cars and the rest.  There is a subtle factor, something that psychologists call the Locus of Control.  Rich people feel like they have control over their lives, poor people feel like they have no control.  As this Locus shifts from the positive to negative, from rich to poor, profound shifts occur in mind and body affecting endocrine and immune function.

The profession of naturopathic doctors descends from the European nature cure movement of centuries past which placed great value on the natural elements as possessing active healing action.  Fresh air, mountain streams and sunlight were considered and used as active healing agents.  Breathing fresh air has intrinsic value that is more than its mere absence of pollutants. 

Now here is the thing that stands out and which has prompted this ramble.  Exposure to nature appears to erase the health inequalities caused by disparities in income.  A study published in the 2008 issue of Lancet, “Effect of exposure to natural environment on health inequalities: an observational population study” links these two trains of thought.

In this paper Mitchell and Popham, wondered whether exposure to green space would reduce the expected effects of socioeconomic status on health.  In other words they started with an idea that nature was an equalizer that would erase some of the negative health effects caused by poverty and low social status.

They classified England’s population that had not yet reached retirement age, some 40,813, 236 individuals, into groups based on income and exposure to green space.  They then looked at mortality records of 366, 348 people who died from 2001 to 2005, and looked for associations between what they call ‘income deprivation’ and mortality to see if they varied with green space exposure.    

The researchers found a statistically significant benefit to green space exposure for mortality from all causes and circulatory disease.  Interestingly, no benefit was seen for lung cancer.  Well obviously, those who smoke a cigarette while walking in the park will still get lung cancer.

Comparing all-cause mortality between poorest and richest (most income deprived versus least income deprived) people produced results similar to other studies.  The poor who had the lowest exposure to green space had an incidence rate ratio (IRR) of 1.93, almost twice as high as the rich. Those with the most exposure to green areas had a significantly lower IRR; it dropped to 1.43.  A similar though  larger benefit was seen for circulatory disease.  In simple words, the more someone is exposed to ‘green environments’ the less detrimental the effect caused by poverty on their health.  Here’s how Mitchell and Popham sum it up:

“Populations that are exposed to the greenest environments also have lowest levels of health inequality related to income deprivation. Physical environments that promote good health might be important to reduce socioeconomic health inequalities.”

This is a profound argument for creating more green spaces in our cities especially low income areas and for providing opportunities for those living in cities to get out into a green space.

The heavy rains this summer have created some interesting changes in my dog walks.    A combination of inept maintenance and then inattention on the part of the park management has allowed nature to take an unexpected course.  Last summer a ditch was dug on either side the dirt road that runs through the area for drainage purposes.  This summer, the river rose unusually high with the June rains, enough so that it crested the bank and reached the road’s drainage ditch.  Though a gradual at first, the stream crept into the ditch and began to flow down it, taking a short cut through the marshes toward the ‘turtle pond.’ What started as a small ditch rapidly eroded away, within a few days it diverted the entire stream flow into the pond.  Though exciting to watch, the normally gentle stream turned into a torrent wiping out footpaths and limiting access to much of the walking area.  Rumor has it that a dog was swept away and drowned and then a child almost met the same fate.  The pond that had provided a summer long swimming hole for dogs has filled in with sand.  Swimming hose aside,  the stable pond ecosystem of bullfrogs and ancient turtles has vanished.

This week a sign was put up at the parking lot today explaining that the park is debating whether they should continue to allow dog walkers to use this off leash area.  In the original plans for the park, this open area was apparently set aside to train hunting dogs.   

Information about the park’s plans on limiting use of the dog walk areas at Cherry Creek State Park can be viewed at:

http://parks.state.co.us/Parks/CherryCreek/Dogtrainingarea/

Comments can be sent to the park administration at:

dogtrainingarea.process@state.co.us

  What are defined as ‘green spaces’ by researchers are a weak substitute for the alpine mountain experience promoted by some of our forbears.  If one believes the premise of homeopathy, that water can preserve some trace of past chemical exposuress, than it is easy to assume pure spring water may have benefit that extends past its mere absence of pollutants.  The Japanese have a term for the health benefits of ‘forest walking.’ They call it Shinrin-yoku. and research suggests it has both a physiological and psychological benefits.   Though our beliefs in this area may set us apart from some medical thinkers, our profession agrees in principle with the major premises of the determinants of health.

Environ Health Prev Med. 2009 Jul 9. [Epub ahead of print]Click here to read Links

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

    Tsunetsugu Y, Park BJ, Miyazaki Y.

    Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan, yukot@ffpri.affrc.go.jp.

    "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.

Environ Health Prev Med. 2009 May 2. [Epub ahead of print]Click here to read Links

    The physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing): evidence from field experiments in 24 forests across Japan.

    Park BJ, Tsunetsugu Y, Kasetani T, Kagawa T, Miyazaki Y.

    Center for Environment, Health and Field Sciences, Chiba University, Kashiwa-no-ha 6-2-1, Kashiwa, Chiba, 277-0882, Japan, bjpark@faculty.chiba-u.jp.

    This paper reviews previous research on the physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing), and presents new results from field experiments conducted in 24 forests across Japan. The term Shinrin-yoku was coined by the Japanese Ministry of Agriculture, Forestry, and Fisheries in 1982, and can be defined as making contact with and taking in the atmosphere of the forest. In order to clarify the physiological effects of Shinrin-yoku, we conducted field experiments in 24 forests across Japan. In each experiment, 12 subjects (280 total; ages 21.7 +/- 1.5 year) walked in and viewed a forest or city area. On the first day, six subjects were sent to a forest area, and the others to a city area. On the second day, each group was sent to the other area as a cross-check. Salivary cortisol, blood pressure, pulse rate, and heart rate variability were used as indices. These indices were measured in the morning at the accommodation facility before breakfast and also both before and after the walking (for 16 +/- 5 min) and viewing (for 14 +/- 2 min). The R-R interval was also measured during the walking and viewing periods. The results show that forest environments promote lower concentrations of cortisol, lower pulse rate, lower blood pressure, greater parasympathetic nerve activity, and lower sympathetic nerve activity than do city environments. These results will contribute to the development of a research field dedicated to forest medicine, which may be used as a strategy for preventive medicine.

Public Health. 2007 Jan;121(1):54-63. Epub 2006 Oct 20.Click here to read Links

    Psychological effects of forest environments on healthy adults: Shinrin-yoku (forest-air bathing, walking) as a possible method of stress reduction.

    Morita E, Fukuda S, Nagano J, Hamajima N, Yamamoto H, Iwai Y, Nakashima T, Ohira H, Shirakawa T.

    Department of Health Promotion and Human Behaviour, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501, Japan. morita@pbh.med.kyoto-u.ac.jp

    OBJECTIVES: Shinrin-yoku (walking and/or staying in forests in order to promote health) is a major form of relaxation in Japan; however, its effects have yet to be completely clarified. The aims of this study were: (1) to evaluate the psychological effects of shinrin-yoku in a large number of participants; and (2) to identify the factors related to these effects. METHODS: Four hundred and ninety-eight healthy volunteers took part in the study. Surveys were conducted twice in a forest on the same day (forest day) and twice on a control day. Outcome measures were evaluated using the Multiple Mood Scale-Short Form (hostility, depression, boredom, friendliness, wellbeing and liveliness) and the State-Trait Anxiety Inventory A-State Scale. Statistical analyses were conducted using analysis of variance and multiple regression analyses. RESULTS: Hostility (P<0.001) and depression (P<0.001) scores decreased significantly, and liveliness (P=0.001) scores increased significantly on the forest day compared with the control day. The main effect of environment was also observed with all outcomes except for hostility, and the forest environment was advantageous. Stress levels were shown to be related to the magnitude of the shinrin-yoku effect; the higher the stress level, the greater the effect. CONCLUSIONS: This study revealed that forest environments are advantageous with respect to acute emotions, especially among those experiencing chronic stress. Accordingly, shinrin-yoku may be employed as a stress reduction method, and forest environments can be viewed as therapeutic landscapes. Therefore, customary shinrin-yoku may help to decrease the risk of psychosocial stress-related diseases, and evaluation of the long-term effects of shinrin-yoku is warranted.

    PMID: 17055544

Lancet. 2008 Nov 8;372(9650):1655-60. Comment in:

        Lancet. 2008 Nov 8;372(9650):1614-5.

    Effect of exposure to natural environment on health inequalities: an observational population study.

    Mitchell R, Popham F.

    Public Health and Health Policy, University of Glasgow, Glasgow, UK.

    BACKGROUND: Studies have shown that exposure to the natural environment, or so-called green space, has an independent effect on health and health-related behaviours. We postulated that income-related inequality in health would be less pronounced in populations with greater exposure to green space, since access to such areas can modify pathways through which low socioeconomic position can lead to disease. METHODS: We classified the population of England at younger than retirement age (n=40 813 236) into groups on the basis of income deprivation and exposure to green space. We obtained individual mortality records (n=366 348) to establish whether the association between income deprivation, all-cause mortality, and cause-specific mortality (circulatory disease, lung cancer, and intentional self-harm) in 2001-05, varied by exposure to green space measured in 2001, with control for potential confounding factors. We used stratified models to identify the nature of this variation. FINDINGS: The association between income deprivation and mortality differed significantly across the groups of exposure to green space for mortality from all causes (p<0.0001) and circulatory disease (p=0.0212), but not from lung cancer or intentional self-harm. Health inequalities related to income deprivation in all-cause mortality and mortality from circulatory diseases were lower in populations living in the greenest areas. The incidence rate ratio (IRR) for all-cause mortality for the most income deprived quartile compared with the least deprived was 1.93 (95% CI 1.86-2.01) in the least green areas, whereas it was 1.43 (1.34-1.53) in the most green. For circulatory diseases, the IRR was 2.19 (2.04-2.34) in the least green areas and 1.54 (1.38-1.73) in the most green. There was no effect for causes of death unlikely to be affected by green space, such as lung cancer and intentional self-harm. INTERPRETATION: Populations that are exposed to the greenest environments also have lowest levels of health inequality related to income deprivation. Physical environments that promote good health might be important to reduce socioeconomic health inequalities.

Environ Health Prev Med. 2009 Jul 9. [Epub ahead of print]Click here to read Links

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

    Tsunetsugu Y, Park BJ, Miyazaki Y.

    Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan, yukot@ffpri.affrc.go.jp.

    "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.

Environ Health Prev Med. 2009 May 2. [Epub ahead of print]Click here to read Links

    The physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing): evidence from field experiments in 24 forests across Japan.

    Park BJ, Tsunetsugu Y, Kasetani T, Kagawa T, Miyazaki Y.

    Center for Environment, Health and Field Sciences, Chiba University, Kashiwa-no-ha 6-2-1, Kashiwa, Chiba, 277-0882, Japan, bjpark@faculty.chiba-u.jp.

    This paper reviews previous research on the physiological effects of Shinrin-yoku (taking in the forest atmosphere or forest bathing), and presents new results from field experiments conducted in 24 forests across Japan. The term Shinrin-yoku was coined by the Japanese Ministry of Agriculture, Forestry, and Fisheries in 1982, and can be defined as making contact with and taking in the atmosphere of the forest. In order to clarify the physiological effects of Shinrin-yoku, we conducted field experiments in 24 forests across Japan. In each experiment, 12 subjects (280 total; ages 21.7 +/- 1.5 year) walked in and viewed a forest or city area. On the first day, six subjects were sent to a forest area, and the others to a city area. On the second day, each group was sent to the other area as a cross-check. Salivary cortisol, blood pressure, pulse rate, and heart rate variability were used as indices. These indices were measured in the morning at the accommodation facility before breakfast and also both before and after the walking (for 16 +/- 5 min) and viewing (for 14 +/- 2 min). The R-R interval was also measured during the walking and viewing periods. The results show that forest environments promote lower concentrations of cortisol, lower pulse rate, lower blood pressure, greater parasympathetic nerve activity, and lower sympathetic nerve activity than do city environments. These results will contribute to the development of a research field dedicated to forest medicine, which may be used as a strategy for preventive medicine.

Public Health. 2007 Jan;121(1):54-63. Epub 2006 Oct 20.Click here to read Links

    Psychological effects of forest environments on healthy adults: Shinrin-yoku (forest-air bathing, walking) as a possible method of stress reduction.

    Morita E, Fukuda S, Nagano J, Hamajima N, Yamamoto H, Iwai Y, Nakashima T, Ohira H, Shirakawa T.

    Department of Health Promotion and Human Behaviour, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501, Japan. morita@pbh.med.kyoto-u.ac.jp

    OBJECTIVES: Shinrin-yoku (walking and/or staying in forests in order to promote health) is a major form of relaxation in Japan; however, its effects have yet to be completely clarified. The aims of this study were: (1) to evaluate the psychological effects of shinrin-yoku in a large number of participants; and (2) to identify the factors related to these effects. METHODS: Four hundred and ninety-eight healthy volunteers took part in the study. Surveys were conducted twice in a forest on the same day (forest day) and twice on a control day. Outcome measures were evaluated using the Multiple Mood Scale-Short Form (hostility, depression, boredom, friendliness, wellbeing and liveliness) and the State-Trait Anxiety Inventory A-State Scale. Statistical analyses were conducted using analysis of variance and multiple regression analyses. RESULTS: Hostility (P<0.001) and depression (P<0.001) scores decreased significantly, and liveliness (P=0.001) scores increased significantly on the forest day compared with the control day. The main effect of environment was also observed with all outcomes except for hostility, and the forest environment was advantageous. Stress levels were shown to be related to the magnitude of the shinrin-yoku effect; the higher the stress level, the greater the effect. CONCLUSIONS: This study revealed that forest environments are advantageous with respect to acute emotions, especially among those experiencing chronic stress. Accordingly, shinrin-yoku may be employed as a stress reduction method, and forest environments can be viewed as therapeutic landscapes. Therefore, customary shinrin-yoku may help to decrease the risk of psychosocial stress-related diseases, and evaluation of the long-term effects of shinrin-yoku is warranted.

    PMID: 17055544