The common central idea in both passages is the positive effects of sunlight on health.
In the first passage, it is mentioned that sunlight exposure can reduce blood pressure, lower the risk of heart attacks and strokes, and increase the release of nitric oxide which is beneficial for the body. This is supported by the University of Edinburgh's research on the benefits of sunlight exposure.
In the second passage, it is stated that moderate sun exposure ensures that people get enough vitamin D, which is linked to the prevention of diseases such as multiple sclerosis. It also mentions the correlation between lack of sun exposure, vitamin D deficiency, and Seasonal Affective Disorder (SAD). This is supported by the publication from Harvard Medical School on the benefits of moderate sun exposure.
Therefore, the common central idea is the positive impact of sunlight on health, including reducing the risk of cardiovascular diseases, providing essential vitamin D, and improving overall mood.