Clinical research

This review article, assembled by a team of UV experts, indicates that UV exposure may support multiple internal systems linked to a longer healthspan, including immune regulation, cardiovascular health, metabolic balance, and neuro-endocrine function. UV exposure activates complex neuro-immune-endocrine pathways through the skin that influence systemic physiology. These effects include lowering blood pressure via nitric oxide release, modulating inflammatory and immune responses, supporting metabolic processes related to weight, glucose homeostasis, and adipose tissue function, and influencing hormonal and reproductive pathways. Large cohort studies also associate higher lifetime sunlight exposure with reduced all-cause and cardiovascular mortality, suggesting that sunlight-induced UV signaling may contribute to enhanced longevity and reduced risk of cardiometabolic and inflammatory diseases.

In this study that looked at UV light exposure and mortality data for over 500,000 individuals, UV exposure was inversely associated with all-cause, cardiovascular disease (CVD) and cancer mortality. Solarium users were also at a lower risk of non-CVD and non-cancer mortality.

This paper by vitamin D expert Dr. Holick compares the 2024 and 2011 Endocrine Society Clinical Practice Guidelines on vitamin D and explains why concentrations of 25-hydroxyvitamin D should be at least 30 ng/mL with a preferred range of 40-60 ng/mL as recommended by the 2011 Guidelines in order to obtain maximum extra skeletal benefits from vitamin D including reducing risk of upper respiratory tract infection for children and adults, autoimmune disorders, pre-eclampsia, low birth weight, neonatal dental caries, and deadly cancers.

This review article by ultraviolet expert Richard Weller highlights that while ultraviolet radiation is known as a skin carcinogen, many studies correlate sun exposure with reduced all-cause, cardiovascular, and cancer mortality. The paper suggests that sunlight may confer health benefits beyond vitamin D synthesis, such as the photomobilization of nitric oxide from skin stores, which can reduce cardiovascular morbidity.

This systematic review of 289 articles concluded that data strongly suggested that maintaining serum vitamin D concentrations of more than 50 ng/mL is associated with significant risk reduction from viral and bacterial infections, sepsis, and autoimmunity.

The article discusses the benefits of UV light independent of vitamin D supplementation, including increased production of nitric oxide which reduces blood pressure and generally improves cardiovascular health, protective effects of increased melanin in the skin which can act as a sunscreen, suppressed symptoms from multiple sclerosis, improved mood and energy through released endorphins, and improved immunity through modulation of various cytokines and enzymes.

This report summarizes research on the roles for vitamin D in cancer, immunity and autoimmune diseases, cardiovascular and respiratory health, pregnancy, obesity, erythropoiesis, diabetes, muscle function, and aging.

Solar UV has been inversely correlated with geographical and seasonal variation in many health conditions, including cardiovascular disease and respiratory infections. This article discusses how this effect could be impacted by various factors, including nitric oxide production, heat, vitamin D, and gene expression. The author, vitamin D expert William Grant, recommends increasing exposure to summer sunlight without sunburn to improve health.