The Impact of Natural Sunlight on Quality of Life and Psychological Well-Being

Abstract Sunlight is widely assumed to enhance well-being. However, systematic reviews suggest that the evidence is less extensive and partly inconsistent than commonly assumed. In this study, n = 120 predominantly young adults completed an online survey assessing quality of life (WHOQOL-BREF) and well-being (FAHW). Participants additionally reported how much time they had spent outdoors and at which locations during the preceding 14 days. These self-reports were matched with local and temporal data from the German Weather Service to estimate each participant’s individual sunshine duration. Correlation analyses revealed significant but small associations between sunshine duration and well-being, as well as between sunshine duration and three of the four quality-of-life domains. The findings support the assumed relationship between sunshine duration, quality of life, and well-being, while also demonstrating a novel approach to determine individual sunshine duration. Future studies should validate this method with larger and more diverse samples. Although increased sun exposure is associated with a higher risk of skin cancer, this aspect was beyond the scope of the present study. The proposed approach may also be applied to studies on artificial light exposure to control for participants’ natural daylight exposure (light history). Competing Interest Statement The authors have declared no competing interest. Funding Statement The author(s) received no specific funding for this work. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The experiment was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of Medical School Hamburg (MSH-2022/151). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the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 Data Availability The data have been submitted as supplementary material.