ORIGINAL RESEARCH article
Front. Environ. Health
Sec. Housing Conditions and Public Health
Volume 4 - 2025 | doi: 10.3389/fenvh.2025.1601838
This article is part of the Research TopicUrban Nature and its Benefits for Human HealthView all articles
Physiological Effects of A Small Green Space Installed on The Side of A Clinic for Outpatients with Depression
Provisionally accepted
- 1Center for Environment, Health and Field Sciences, Chiba University, Kashiwa, Japan
- 2Institute for Advanced Academic Research, Chiba University, Chiba, Japan
- 3Department of Forest Science, Kongju National University, Chungcheongnam-do, Republic of Korea
- 4Nozaki Clinic, Tokyo, Japan
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Depression rates have been rising globally, making it a significant public health concern. Increasing evidence suggests that exposure to natural environments has positive effects on mental health. However, most studies on the restorative effects of nature have focused on healthy individuals, with limited data available on vulnerable populations, such as patients with depression. This study examined the physiological and psychological relaxation effects of viewing a small urban green space (biotope) on outpatients with depression. Conducted in an urban clinical setting, this crossover study involved 28 adult male outpatients with major depressive disorder. The experimental condition involved viewing a biotope outside the clinic, while the control condition involved viewing a building facade. Heart rate variability was used as a physiological indicator, while subjective evaluations were conducted using the modified semantic differential method and the Profile of Mood States 2nd Edition (POMS 2) short version. Results indicated that biotope viewing significantly increased parasympathetic nervous activity while decreasing sympathetic nervous activity. Subjectively, participants reported increased comfort, relaxation, and naturalness. POMS 2 assessments further revealed a significant reduction in negative affect scores and an increase in positive affect scores. This study provides empirical evidence that integrating small-scale urban greenery into clinical environments can promote relaxation and well-being in individuals with depression. Given the high levels of stress in urban populations, particularly in overcrowded cities like Tokyo, incorporating accessible green spaces in urban planning may serve as a viable intervention to mitigate environmental health disparities and improve mental health outcomes.
Keywords: Autonomic nervous activity, biotope, Urban greenery, Heart rate variability, Major Depressive Disorder, Nature therapy, Physiological relaxation, Well-being
Received: 28 Mar 2025; Accepted: 05 Aug 2025.
Copyright: © 2025 Ikei, Song, Sagasaki, Nozaki and Miyazaki. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Harumi Ikei, Center for Environment, Health and Field Sciences, Chiba University, Kashiwa, Japan
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.