Exposure to sunlight occurs because exposure to sunlight causes the skin to produce more melanin and to darken. The tan fades as these cells move toward the surface and are sloughed off. Too much exposure to ultraviolet or UV rays can cause sunburn.
Sunshine is a mixed blessing. There’s no question that it can be a danger to your skin. The ultraviolet (UV) radiation emitted by the sun is a known carcinogen. But moderate sun exposure may have benefits for your health, including stronger bones, better sleep, improved mood, and a healthier immune system.
Regular sun exposure is the most natural way to get enough vitamin D. To maintain healthy blood levels, aim to get 10–30 minutes of midday sunlight, several times per week. People with darker skin may need a little more than this. Your exposure time should depend on how sensitive your skin is to sunlight.
A lack of sunlight can cause a multitude of problems such as weak bones, foot deformities, some cancers, depression, skin problems, weight gain and cognitive issues.