A systematic review of Flotation-Restricted Environmental Stimulation Therapy (REST)

Background Restricted Environmental Stimulation Therapy (REST) is a therapeutic technique that involves immersing an individual in an environment with minimal sensory input or stimulation. The goal of REST is to induce a state of relaxation that is deeper than what can be achieved through other forms of relaxation techniques. Research suggests that REST can help reduce anxiety, alleviate chronic pain, improve sleep, and enhance creativity and cognitive function. Flotation-REST is a popular type of REST that utilizes an enclosed tank filled with buoyant saltwater to facilitate relaxation. This study aimed to synthesize the evidence on studies that investigate the effects of flotation-REST. Methods We used PRISMA to survey the flotation-REST literature from 1960 to 2023. This search was conducted on 29 January 2023 within the Google Scholar and PubMed databases. Journal and conference papers, as well as electronic preprints, that used flotation-REST in their methods, were written in English, and were published in or after 1960 were included; non-original research papers (e.g., review papers, book chapters, and papers solely on types of REST other than flotation-REST (e.g., chamber-REST) were excluded. From each eligible paper, we extracted information regarding the participant sample, application of flotation-REST, experimental design, treatment delivery method, questionnaires and tools, and study results. Results In total, we found 60 studies that included 1,838 participants. We propose that the application of flotation-REST can be divided into nine main categories: pain, athletic performance, physiology, stress, consciousness, psychology, creativity, clinical anxiety, sleep, smoking cessation, and other miscellaneous applications. In general, flotation-REST was found to bring about positive effects on pain, athletic performance, stress, mental well-being, and clinical anxiety, while having limited to no effect on sleep-related disorders and smoking cessation. Conclusion This paper provides a comprehensive overview of the current research on flotation-REST, highlights ongoing limitations in the literature, and outlines potential areas for future research. While flotation-REST appears to induce various benefits for physical and mental well-being, particularly when it comes to managing states like pain and stress, more research is needed to better understand the mechanisms underlying these effects and to identify optimal treatment protocols for different populations. A limitation of this paper is the relatively small number of studies available for review, which limits the generalizability of certain findings and highlights the need for additional research in this area. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The publication received support from the Intramural Research Program of the NIH, NINDS, and a joint grant from the John Templeton Foundation and the Fetzer Institute. The views expressed herein are solely those of the author(s) and do not necessarily represent the opinions of NINDS, the John Templeton Foundation, or the Fetzer Institute. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes NA