The sun produces ultraviolet radiation that reaches Earth in two main forms: UVA and UVB rays. Both penetrate skin differently and pose distinct health risks. UVA rays penetrate deeply into the skin's dermis layer, contributing to premature aging and wrinkles. UVB rays damage the epidermis, the outermost layer, causing sunburns and playing a direct role in melanoma and other skin cancers.
UV exposure varies throughout the day and by location. The UV index, measured on a scale from 0 to 11 or higher, tells you how intense ultraviolet radiation is at ground level. Higher numbers mean greater risk. UV levels peak between 10 a.m. and 4 p.m., when the sun is highest in the sky. Reflective surfaces like water, sand, and snow intensify exposure by bouncing rays onto your skin.
Paradoxically, some UV exposure benefits health. Sunlight triggers vitamin D synthesis in skin, essential for bone health, immune function, and mood regulation. Most people need 10 to 30 minutes of midday sun several times weekly for adequate vitamin D production, depending on skin tone and latitude.
Protection requires a layered approach. Broad-spectrum sunscreen with SPF 30 or higher blocks both UVA and UVB rays. Apply generously, about one-quarter teaspoon to your face, and reapply every two hours or after swimming. Physical barriers work effectively too. Wear UV-blocking clothing, wide-brimmed hats, and sunglasses that block 99 percent of UV radiation. Seek shade during peak hours whenever possible.
Your skin type influences burn risk. Darker skin contains more melanin, which provides natural UV protection, but Black and Brown individuals still develop skin cancer and need protection. Fair-skinned