The research: Researchers from several Boston hospitals and Harvard Medical School exposed shaved mice to low levels of UV light 5 days a week for 6 weeks. Blood draws showed that levels of beta endorphin, an endorphin produced by the pituitary gland that suppresses pain and acts through the same pathway as addictive opiates like heroin and morphine, increased after just 1 week of exposure. After the treatment ended, researchers gave the mice opiate-blocking drugs and found that the mice experienced withdrawal symptoms like shaking, tremors, and teeth chattering. What it means: Chronic UV exposure could potentially lead to addiction-like behavior and even physical dependence. The researchers can’t say for sure how much UV exposure it would take to produce the same kind of results in humans, “but there are people who appear to be addicted to sunbathing, going to indoor tanning beds, and exposing themselves to UV and trying to darken their skin to a point where it just simply doesn’t look healthy anymore,” says David Fisher, MD, study author and chairman of the department of dermatology at Massachusetts General Hospital. (After all, who could forget Tanning Mom?) The bottom line: “This study doesn’t mean that being out in the sun is equivalent to injecting yourself with heroin. Opiate drugs can be given in doses that are like a nuclear bomb—this is not that level of pharmacology at work. But you could argue that UV exposure is much more insidious,” cautions Fisher. So take the necessary precautions. Above all else, avoid tanning beds. And when you’re outside, practice sun safety habits like applying sunscreen with a minimum of SPF 30, wearing wide brim hats, and avoiding the sun when it’s at its peak strength (between 10 AM and 4 PM).
