Evolution of human salivary stress markers during an eight-hour exposure to a Mediterranean holm oak forest. A pilot study

The current study analyses the evolution of different human stress markers during an 8 h exposure to a Mediterranean Holm oak forest. We conducted a pre-post study with thirty-one subjects in which saliva samples were collected before the exposure (baseline) and after 1, 2, 4 and 8 h. Our results show: (A) a significant decrease in cortisol saliva concentrations from the second hour until the end compared to basal time; (B) a significant increase in alpha amylase activity after the first hour of exposure compared to basal time that remained elevated during the rest of the study; (C) a significant decrease in IgA from the fourth hour of exposure compared to the basal time. These findings indicate an effect of forest exposure in salivary biomarkers of stress and provide relevant data for the scientific and healthcare community encouraging further research in the field.