Why it’s OK: It’s no wonder a good mood is referred to as a “sunny” disposition. Basking in the sun’s ultraviolet rays stimulates the production of endorphins -- those feel-good chemicals linked to exercise. And when exposed to the sun’s UV-B rays, your skin manufactures vitamin D, the so-called sunshine vitamin that helps keep bones healthy, and may protect against autoimmune diseases and some cancers.
When to indulge: For vitamin D, spend time in the sun sans sunscreen (which blocks D production) during the middle of the day, when UV-B rays can penetrate the atmosphere, says Michael F. Holick, Ph.D., M.D., professor at Boston University School of Medicine and author of The Vitamin D Solution. If you have fair skin, you can get the vitamin D you need (1500-2000 IUs for most adults) by exposing your arms and legs between 10 a.m. and 3 p.m. in the spring, summer, and fall for 10-15 minutes, three or four times per week. If you have dark skin, you’ll need 5 to 10 times as much exposure, says Holick.
Don’t overdo it: Too much sun is responsible for 90 percent of wrinkles, age spots and other age-related skin changes. UV exposure resulting in sunburns is to blame for 65 percent of all melanoma cases (the most deadly form of skin cancer; however, occupational sun exposure has been demonstrated to decrease the risk of melanoma), and 90 percent of other skin cancers. When spending more than 10-15 minutes outside -- especially at the beach or park -- wear sunscreen from head to toe and reapply every two hours.