Category Archives: Physical Environment

More green space equals less stress (as measured by cortisol)

A project team which includes Rich Mitchell has just published a study showing that cortisol circulation (a marker of stress) is more favourable in areas with greater amounts of green space. The team was led by Catharine Ward Thompson, at OpenSpace research centre. The study is the first to show effects of green space on biomarkers of stress in everyday (i.e. non-experimental) settings. It’s published in Landscape and Urban Planning and you may be able to read it here . The study is part of the wider GreenHealth project, in which CRESH plays a large part. It was funded by the by the Scottish Government’s Rural and Environment Science and Analytical Services (RESAS) Division. For those without access to the journal, here’s the abstract:

Green space has been associated with a wide range of health benefits, including stress reduction, but much pertinent evidence has relied on self-reported health indicators or experiments in artificially controlled environmental conditions. Little research has been reported using ecologically valid objective measures with participants in their everyday, residential settings. This paper describes the results of an exploratory study (n = 25) to establish whether salivary cortisol can act as a biomarker for variation in stress levels which may be associated with varying levels of exposure to green spaces, and whether recruitment and adherence to the required, unsupervised, salivary cortisol sampling protocol within the domestic setting could be achieved in a highly deprived urban population. Self-reported measures of stress and general wellbeing were also captured, allowing exploration of relationships between cortisol, wellbeing and exposure to green space close to home. Results indicate significant relationships between self-reported stress (P < 0.01), diurnal patterns of cortisol secretion (P < 0.05), and quantity of green space in the living environment. Regression analysis indicates percentage of green space in the living environment is a significant (P < 0.05) and independent predictor of the circadian cortisol cycle, in addition to self-reported physical activity (P < 0.02). Results also show that compliance with the study protocol was good. We conclude that salivary cortisol measurement offers considerable potential for exploring relationships between wellbeing and green space and discuss how this ecologically valid methodology can be developed to confirm and extend findings in deprived city areas to illuminate why provision of green space close to home might enhance health.

CRESH at the EUPHA conference on Public Health and Nature

Rich Mitchell is giving a keynote address at a pre-meeting of the European Public Health Association in Copenhagen on the 9th November. Rich will be talking about Public Health’s new found interest in natural environments, the demand for high quality evidence and the relationships between experimental and observational studies. More details on the meeting can be found here.

Mental health and the environment symposium: some thoughts

The CRESH symposium on mental health and the environment was one of those (quite rare) conference days that worked incredibly well. I’m not sure what it was that made the day so interesting and exciting. Perhaps it was the unusual mix of academics, practitioners, policy makers and GPs in the audience, all of whom seemed keen and willing to engage and debate. Perhaps it was the variety of interesting presentations. Whatever the magic ingredients, I came away from the day inspired and full of thoughts. I’d like to share two of them

1) There was much discussion during the day about the nature of ‘evidence’ for the influence of environment on health. There was a clear tension between the desire for evidence from ‘intervention / evaluation’ type studies, which hold the promise of identifying causal mechanisms and offer a higher standard of ‘proof’ about whether environment does or does not hold influence over health (especially if the studies are controlled in some way), and the bulk of existing evidence which stems from observational designs. It certainly feels like the balance of funding available for health research is shifting rapidly to favour study designs which are more experimental than observational. Colleagues of mine have recently had funding requests turned down because of their observational study design, and we have had papers rejected from leading medical journals specifically because of an observational design. This pressure is, rightly or wrongly, asking scientists to work further up the hierarchy of study designs. What concerns me is the extent to which we are ignoring the weakness of experimental / evaluation study designs, especially in a) the extent to which they have external validity (i.e. can we really learn anything about how the wider world works from the controlled and unusual situations that experimental studies either create or exploit) and b) the extent to which we are tempted to believe that what are often relatively short-term studies can really tell us much about how social and physical environments really influence population health and health inequalities. This is a topic to which we intend to return in the next CRESH event. What is the right balance between experimental and observational studies in a portfolio, or mixed economy, of evidence? Is it all over for observation?

2) Critical thinking is essential to the progress of science. If we don’t ask how, and for whom, our results or conclusions might not hold, our work is weaker. If we don’t question how and why we think and research in the way we do, our approaches will not develop. In one area CRESH researches, the health effects of contact with green spaces or natural environments, we frequently encounter land managers, policy makers and planners who adhere to a general orthodoxy that ‘green space is good for you’. The value of critical science is that it makes us aware that not everyone feels comfortable walking in the woods or the park, and that some people even feel threatened by open spaces in the their neighbourhoods. There is plenty of evidence from qualitative and quantitative studies that this is true.

One of the weaknesses of critical thinking in the field at the moment however is that the critique seems to stop at ‘not everyone benefits from green space’. My question is, what do we do with that knowledge? If we can understand how and for whom benefits are not realised, that could help adjust expectations about what green space can deliver, and also help us think through how benefits could be brought to a wider range of people. Perhaps the real value of critical approaches to thinking about environment and health is that they pose these questions.

News about the next CRESH symposium will appear on the site soon. In the meantime, if any attendees want to post their thoughts on the mental health and environment day, please use the form below.

This is a personal post, written by Rich Mitchell. It doesn’t represent the views of ‘CRESH’

Our green space work in the news

Green spaces keep men healthy

Jun 21, 2010

Recent work by Dr Elizabeth Richardson and Prof Richard Mitchell attracted considerable media interest recently.

Their study found that men who live in neighbourhoods with more green space are less likely to die from cardiovascular and respiratory diseases – conditions that account for almost half of all deaths in the UK. But it also found that these benefits of greener neighbourhoods do not extend to women. The results were a surprise because it had previously been widely assumed that green spaces are equally good for everyone, through offering opportunities for physical activity and social contacts for example. The reasons for the findings were unclear, but other literature tells us that women use green space less than men and don’t exercise as much there, particularly if they perceive the area to be unsafe or threatening. This could explain the findings.

The study was the first to study green space and health relationships for the UK as a whole, as the researchers combined remotely sensed data and Ordnance Survey map data to quantify green space at a national level. Mortality statistics based on a population of almost 30 million adults were used, giving the results substantial significance. It should be stressed that as the study only considered mortality statistics it cannot be assumed that women’s health does not benefit from green space in other ways.

The paper “Gender differences in relationships between urban green space and health in the United Kingdom” was funded by the Forestry Commission and originally published in the journal Social Science and Medicine, but has now received diverse coverage through outlets such as BBC Radio Scotland, the Daily Telegraph, and even The Sun, where the headline read “Park life is better for blokes’ hearts”.

Links:

Daily Mail: “Why living near a park is good for a man’s heart and lungs”

Scotsman: “Women miss out on health benefit of green spaces, major study finds”

Scottish Sun: “Park life is better for blokes’ hearts”