
06/30/2025
Here’s a bullet-point breakdown of how sunlight—especially UV—affects health:
Vitamin D synthesis (UVB): UVB rays convert skin cholesterol into vitamin D₃, essential for strong bones, immunity, and reduced risk of some cancers and chronic diseases
Nitric oxide release (mainly UVA): UVA triggers skin to release nitric oxide, relaxing blood vessels and lowering blood pressure, supporting cardiovascular health
Immune modulation: UV exposure induces immunoregulatory responses—like cytokines, regulatory T and B cells—helping prevent autoimmune conditions while also temporarily suppressing anti-tumor immunity.
Mood, sleep & neurochemical effects: UVB boosts serotonin and endorphins (enhancing mood), while visible light influences melatonin and circadian rhythms—benefiting sleep and possibly reducing seasonal depression
Metabolic & cancer protection: Moderate regular sun correlates with lower risks of cancers (colon, breast, prostate, lymphoma), metabolic syndrome, hypertension, and even obesity—beyond vitamin D effects