The continuously growing body of experimental evidence that experiencing nature, being in the company of plants, natural light, and engaging in horticultural activities provides therapeutic and well-being benefits is unquestionable. While there has been an abundance of research on the benefits of being in natural environments and/or engaging in people-plant activities, too many studies have been experimentally narrowly focused and involved small sample sizes, thereby limiting statistical robustness and wider applicability to the general population.
However, it is recognized that the biophilic characteristics of being in nature and involvement in people-plant activities, when introduced into confined environments, can enhance human health and well-being.
Zandi and Wung1 conducted a systematic search, evaluation, and review of the health outcomes, identifying 124 published research studies involving edible greens and biophilic elements in confined environments.
The authors searched the PubMed and Scopus databases using PRISMA2 criteria for systematic reviews and meta-analyses, selecting the 124 studies for further analysis. Inclusion criteria for the studies encompassed the following: peer-reviewed studies involving human or human-analog contained or isolated environments, comparator settings were both conventional and non-biophilic environments; and assessed outcomes included physiological, psychological, and behavioral assessments of well-being.
The authors concluded from their analysis that there was an emerging consensus that biophilic interventions in both confined and clinical environments had measurable stress-reduction benefits. In space travel and Earth-based space analog environments, controlled-environment plant growth modules not only provided fresh greenery but also conferred psychological benefits to the inhabitants.
From the collected studies, the authors found that greenery in hospitals, elder care facilities, and space travel habitats reduced stress, improved moods, and overall well-being. The recorded therapeutic benefits were determined to be consistent with the Stress Reduction and Attention Restoration theories. The authors concluded that the implementation of biophilic elements in confined built environments on Earth and in outer space holds promise to enhance human health and resilience.
The authors observed and confirmed that the existing evidence on biophilic interventions often relied on preliminary or pilot studies with small sample sizes. The authors concluded there is a critical need for large-scale randomized controlled trials to verify and extend the reliability and validity of reported outcomes and therapeutic benefits.
A possible next step for the present systematic review is to conduct a meta-analysis of the included studies to provide an overall quantitative assessment of the health and well-being benefits of the biophilic interventions, thereby strengthening the collective empirical evidence.
1Zandi, A. and Wung, S.F. (2025). Health Effects of Plants, Light, and Natural Elements of Biophilic Interventions in Confined Settings: A Systematic Review. Frontiers in Physiology, 16, 1700518. https://doi.org/10.3389/fphys.2025.1700518
2https://www.prisma-statement.org/
Charles Guy, Emeritus and Courtesy Professor
Department of Environmental Horticulture, University of Florida
Steering Committee, Wilmot Botanical Gardens, University of Florida