The Effect of Biophilic Architecture on Stress Reduction and Improvement of Quality of Life

Abstract

Biophilic design (the integration of natural elements into built environments) has been proposed as a potential strategy for reducing stress and enhancing quality of life; however, controlled and quantitatively documented experimental evidence regarding its effectiveness in indoor contexts remains limited. The aim of the present study was to examine the effect of a standardized biophilic intervention on perceived stress and quality of life in adults. This study employed a quasi-experimental design. Adult participants (18–65 years) residing in Isfahan Province who spent at least 20 hours per week in the studied environment were randomly assigned to either an intervention group (environment modified with plants, increased natural lighting, and natural materials/surfaces; n = 64) or a control group (unchanged environment; n = 64). The intervention period lasted 8 weeks. Variables were measured exclusively using self-report instruments: perceived stress was assessed using the Perceived Stress Scale–10 (PSS-10), and quality of life was measured using the WHOQOL-BREF. Analyses included linear mixed models (LMM) to test the group × time interaction and comparisons of pre–post change scores (Δ). At baseline, the mean PSS score was 18.7 ± 6.1 in the control group and 18.4 ± 6.0 in the intervention group. Following the intervention, mean PSS scores were 17.8 ± 6.3 and 14.1 ± 5.2, respectively. The group × time interaction for PSS was significant (β = −3.20, SE = 0.80, t = −4.00, p < .001; 95% CI [−4.80, −1.60]). The mean change in PSS (ΔPSS) was −4.3 (SD = 5.0) in the intervention group and −0.9 (SD = 4.8) in the control group (between-group difference = −3.4; 95% CI [−5.0, −1.8]; p < .001; Cohen’s d ≈ 0.68). A significant group × time interaction was also observed for WHOQOL-BREF (β = +4.50, SE = 1.40, t = 3.21, p = .0016; 95% CI [+1.70, +7.30]). The mean change in WHOQOL scores (ΔWHOQOL) was +6.1 (SD = 8.0) in the intervention group and +1.0 (SD = 7.6) in the control group (difference = +5.1; 95% CI [+2.0, +8.2]; p = .0016; Cohen’s d ≈ 0.45). In this selected sample, a practical and relatively simple biophilic intervention implemented in indoor environments resulted in a significant reduction in perceived stress and improvement in quality of life after 8 weeks. The findings suggest that integrating natural elements into interior design may serve as an effective and feasible strategy for promoting psychological well-being. Future research with larger samples, long-term follow-up, and physiological and behavioral assessments is required to clarify mechanisms of action and the durability of outcomes.