Impact of Viewing vs. Not Viewing a Real Forest on Physiological and Psychological Responses in the Same Setting

Abstract

We investigated the impact of viewing versus not viewing a real forest on human subjects’ physiological and psychological responses in the same setting. Fifteen healthy volunteers (11 males, four females, mean age 36 years) participated. Each participant was asked to view a forest while seated in a comfortable chair for 15 min (Forest condition) vs. sitting the same length of time with a curtain obscuring the forest view (Enclosed condition). Both conditions significantly decreased blood pressure (BP) variables, i.e., systolic BP, diastolic BP, and mean arterial pressure between pre and post experimental stimuli, but these reductions showed no difference between conditions. Interestingly, the Forest viewing reduced cerebral oxygenated hemoglobin (HbO2) assessed by near-infrared spectroscopy (NIRS) and improved the subjects’ Profile of Mood States (POMS) scores, whereas the Enclosed condition increased the HbO2 and did not affect the POMS scores. There were no significant differences in saliva amylase or heart rate variability (HRV) between the two conditions. Collectively, these results suggest that viewing a real forest may have a positive effect on cerebral activity and psychological responses. However, both viewing and not viewing the forest had similar effects on cardiovascular responses such as BP variables and HRV.

Walking economy at simulated high altitude in human healthy young male lowlanders

“…Hb concentrations received by detector 1 were subtracted from those received by detector 2. This procedure allowed us to minimize the influence of skin blood flow (Ando et al, 2013; Horiuchi et al, 2014a), and to provide a NIRS signal traversing approximately 20 mm, because it has been reported that NIRS signals can reach a half of the depth of the distance between the probe and detector (Patterson et al, 1989). …”

Effects of Forest Therapy on Depressive Symptoms among Adults: A Systematic Review

“…About one third of the studies [23,[26][27][28][29]32,34,39] offered forest therapy programs and control conditions (such as activities in downtown) every other day during the two-day periods. Three studies [12,21,25] used a one-time intervention that lasted a few hours to half a day. One study did not report duration details of the intervention [36].…”

“…For articles published in English, nine studies [12,19,21,22,25,28,29,34,39] used POMS to assess the level of depression and three studies [28,29,39] used Semantic differential (SD) method. Other scales used by the studies included the Hamilton Rating Scales for Depression [20], Beck Depression Inventory (BDI) [16,20,24,31], positive and negative affect schedule (PANAS) [34].…”

“…Other scales used to measure depression were the Hospital Anxiety and Depression Scale (HADS) [38], Hamilton Rating Scales for Depression [17], Montgomery-Asberg Depression Rating Scales [17], Symptom Check List (SCL-90-R) [32], and Zung Self-Rating Depression Scale (SDS) [36]. Fourteen studies [13,15,[17][18][19][21][22][23][24][25][26]28,29,39] used both self-report, paper-and-pencil questionnaires, and physiological measures, while 14 studies [12,14,16,20,27,[30][31][32][33][34][35][36][37][38] used only selfreport, paper-and-pencil questionnaires. Physiological or objective measures included heart rate variability (HRV), blood pressure, heart rate, and amylase concentration.…”

“…Based on the SIGN checklist, ten out of the twenty-eight studies [16,[18][19][20][21]23,25,30,34,37] met an "acceptable quality" rating and the rest eighteen studies were rated as low quality [12][13][14][15]17,22,24,[26][27][28][29][31][32][33]35,36,38,39]. Six studies [16,[18][19][20][21][22] used random allocations; however, no detailed description of the procedure was provided except two studies [18,20].…”