A Systematic Review of Light Therapy on Mental Health on and Beyond Earth

Abstract

Light can influence human emotional well-being, sleep quality, and circadian rhythms. The application of these qualities in a therapeutic context is currently being explored. Research has been conducted into the effects of light therapy on wound healing, sleep enhancement, stress management, and the improvement of depressive symptoms. Despite the extensive amount of studies in this field, a satisfactory framework for categorizing light therapies has yet to be developed. To address this problem, our research team proposes to categorize light therapy by wavelength (color). The benefit of this categorization is that, while therapeutic applications may evolve, the fundamental properties of light colors remain constant. Categorizing by color supports scientific innovation and maintains consistent categories even as new research emerges. On the other hand, light therapy’s potential is undermined. Light therapy is characterized by its affordability, durability, consistency, and minimal side effects. While light therapy is interchangeable with other therapeutic methods in common scenarios, it is specifically suited for environments where all those attributes are essential. Space missions represent one such environment. Space exploration is a major frontier for humanity, yet the mental health and living conditions of astronauts have received limited attention. Space missions present unique environmental challenges to astronauts due to altered light exposure, high-pressure, and isolated living environments. These environmental problems need to be addressed, but the resource-scarce space environment requires a reliable and durable solution. Light therapy’s advantages align well with these constraints. Moreover, its ability to address issues such as disrupted circadian rhythms and psychological stress caused by space environmental problems renders it an optimal intervention for space exploration. This article will examine the therapeutic effects of light therapy, with a particular focus on the ways in which different light colors address various health issues and recent discoveries. The potential of light therapy will be demonstrated through the use of space missions as an illustrative example. Additionally, we will briefly discuss future research directions for light therapy. Our primary objective is to establish an intuitive and stable categorization of light therapy. We will examine the potential of light therapy in unique environments, such as space missions, and discuss how it can address common symptoms experienced during these missions. Our ultimate goal is to fully realize the potential of light therapy in tailored environments and inspire the discovery of other scenarios where light therapy can be equally effective.