PLoS ONE 2017; 12(3): e0172200 -

The effect of randomised exposure to different types of natural outdoor environments compared to exposure to an urban environment on people with indications of psychological distress in Catalonia.

Triguero-Mas M, Gidlow CJ, Martínez D, de Bont J, Carrasco-Turigas G, Martinez-Iniguez T, Hurst G, Masterson D, Donaire-González D, Seto E, Jones MV, Nieuwenhuijsen MJ
"Experimental studies have reported associations between short-term exposure to natural outdoor environments (NOE) and health benefits. However, they lack insight into mechanisms, often have low external and ecological validity, and have rarely focused on people with some psycho-physiological affection. The aim of this study was to use a randomized, case-crossover design to investigate: (i) the effects of unconstrained exposure to real natural and urban environments on psycho-physiological indicators of people with indications of psychological distress, (ii) the possible differential effects of 30 and 30+180 minutes exposures, and (iii) the possible mechanisms explaining these effects."