Recent Study out of Finland
This study results released in December 2013, investigated the psychological (perceived restorativeness, subjective vitality, mood, creativity) and physiological (salivary cortisol concentration) effects of short-term visits to urban nature environments.
Seventy-seven participants visited three different types of urban areas; a built-up city centre (as a control environment), an urban park, and urban woodland located in Helsinki, the capital of Finland.
The results show that the large urban park and extensively managed urban woodland had almost the same positive influence, but the overall perceived restorativeness was higher in the woodland after the experiment.
The findings suggest that even short-term visits to nature areas have positive effects on perceived stress relief compared to built-up environment. The salivary cortisol level decreased in a similar fashion in all three urban environments during the experiment. The relations between psychological measures and physiological measures, as well as the influence of nature exposure on different groups of people, need to be studied further.
So, enjoy your local greenspace!