Sunbathing is addictive
Soaking up UV rays creates rush of feel-good chemicals ‘like heroin use’
IF you spend hours in the sun despite knowing how dangerous it can be, you’re not alone.
Because a study suggests that sunbathing is addictive – and affects the brain in a way similar to heroin.
Harvard scientists claim exposure to sunlight prompts the body to produce endorphins, chemicals that ease pain and make us feel good.
They discovered that mice which were regularly exposed to sunlamps showed signs of addiction, and went into withdrawal when they were deprived of their fix.
The finding could help to explain why we find it hard to resist baking on the beach or lying on sunbeds when we know it increases our risk of developing skin cancer.
The disease claims more than 2,000 lives a year and the number of cases has risen seven- fold since sunshine package holidays took off in the 1960s.
The US researchers said: ‘ It’s surprising that we’re genetically programmed to become addicted to something as dangerous as UV radiation, which is probably the most common carcinogen in the world.’
However, British experts have questioned whether the findings, tested on mice, would apply to people.
The team, from Harvard Medical School, gave mice a daily dose of UV light for six weeks. The amount was equivalent to 20 to 30 minutes in the hot Florida sun at midday.
Within a week, the animals’ endorphin levels rose and they became less sensitive to pain. The mice were then given a drug that stops endorphins from working, and quickly developed symptoms of withdrawal such as trembling and chattering teeth. They also went out of their way to avoid the place where they had been given the drug.
Researcher Professor David
‘Genetically programmed’
Fisher described the effect of sunlight as ‘reminiscent of heroin’ but weaker.
He said: ‘This information might serve as a valuable means of educating people to curb excessive sun exposure.’
He added that the addiction may have evolved to ensure the body was getting enough vitamin D. The ‘sunshine vitamin’ is manufactured when our skin is exposed to sunlight. It is credited with warding off Alzheimer’s, keeping the heart healthy, slowing prostate cancer and stopping multiple sclerosis from developing.
Unlike our ancestors, we now have the option of getting vitamin D from supplements, rather than the sun.
Professor Fisher added: ‘We suspect the explanation involves UV’s contribution to vitamin D synthesis in the skin. However, there are much safer and more reliable sources of vitamin D that do not come with carcinogenic risk, so there is real health value in avoiding sunlight as a source of vitamin D.’
It is thought some people are more likely to become addicted to the sun, just as some are more likely to find drugs or alcohol tempting.
Previous studies have found that people who regularly seek out the sun are even able to tell the difference between real and fake UV light.
A week ago, British scientists warned that sun cream alone does not prevent skin cancer, and people should avoid exposure to the worst of the sun.
But Dr Richard Weller, a dermatologist at Edinburgh University who has shown that sunlight cuts blood pressure, said research shows that the more sun people get, the longer they live.
He said: ‘Mice are nocturnal animals covered in fur which avoid the light, so one must be cautious about extrapolating from these experiments to man. If an “addiction” to the sun truly exists in mankind, it suggests to me there is a benefit to it.’
He said that while people don’t need to avoid the sun, the risk of skin cancer means they must try not to get burnt.