More green space is linked to less stress in deprived communities: Evidence from salivary cortisol patterns

Abstract

a b s t r a c tGreen 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.

Green Infrastructure, Green Stormwater Infrastructure, and Human Health: A Review

“…An experimental study found that stress-induced cortisol in men can be reduced by viewing videos of street trees of varying density [20]. Other observational studies investigated depressed urban communities and found that higher densities of trees around residential neighborhoods were associated with heathier cortisol patterns, both in the saliva [21,22] and hair [19] of the residents; that is, people who live in neighborhoods with higher tree density levels have a more regular diurnal cortisol pattern [21] and collect less cortisol residue in their hair [19]. Some studies showed differences between men and women.…”

“…Tree density is positively associated with lower crime rates [43,44,47,48,50], more optimal cortisol patterns [19][20][21]75], lower blood pressure [16,17], lower rates of obesity [62], lower allergy rates [27], higher cognitive development and performance [37,38], lower prescription rates of antidepression medication [40], and better pregnancy outcomes [23][24][25][26].…”

Nature-Based Strategies for Improving Urban Health and Safety

“…79 Green exposure has also been shown to prevent and mitigate stress, anxiety, and depression, [80][81][82][83] especially in urban environments. 81,84,85 Access to green views has been associated with improved mental health in general 86 and more specifically has been shown to reduce mental fatigue and improve coping with stressful settings. [87][88][89] Spending time in a garden or nature has been shown to be an effective therapy for stress-related mental health issues (i.e., nature-based rehabilitation).…”

“…68,117 For instance, percent of green cover within a residential area is a common measure, 85,118 although this measure may not reflect actual exposure to green space. Adults tend to spend between 60 and 70 % of their time at home 119 and the rest of their time at a work or other locations.…”

Do urban environments increase the risk of anxiety, depression and psychosis? An epidemiological study

“…A body of research suggests that having access to green space is associated with improved mental health and can have a greater impact on mental than physical health (Ohta et al, 2007;Sugiyama et al, 2008;Maas et al, 2009;Groenewegen et al, 2011). A number of mechanisms have been proposed to explain this association, including green space as a means for reducing stress and for increasing social cohesion and support (Sugiyama et al, 2008;Stigsdotter et al, 2010;van den Berg et al, 2010;Thompson et al, 2012), although whether it promotes physical exercise The impact of urban-rural environments on mental health 6 is less clear (see Groenewegen et al, 2011 for an overview).The relationship between type of living environment and health is, therefore, potentially multi-faceted.…”