The sun has got his hat on, our moods feel lighter and we are gripped by a desire to soak up some solar rays. But no, we keep being told: the threat of skin cancer makes this potentially lethal. Now, however, scientists are discovering a positive side to sun-worshipping. Even taking the skin-cancer risk fully into account, they say that getting a good dose of sunshine is statistically going to make us live longer, healthier and happier lives.Emerging research indicates that sunlight may protect us against a wide range of lethal or disabling conditions, such as obesity, heart attacks, strokes, asthma and multiple sclerosis. Sunshine has also been shown to boost our libidos and general mood. This is not simply about vitamin D – which our skin manufactures from sunlight. The vitamin helps us build healthy bones and teeth and may protect against bowel cancer. But new research indicates that solar rays benefit our bodies in multiple other ways. Scientists now believe, for example, that exposure to sun prompts our bodies to produce nitric oxide, a chemical that helps protect our cardiovascular system – and the feel good brain-chemical serotonin.A major clue about sunshine’s benefits has emerged from a study of nearly 30,000 Swedish women whose sunbathing habits have been followed for 20 years. In March investigators, from the world-renowned Karolinska Institute in Stockholm, concluded that avoiding the sun is actually as bad for you as smoking.The study, in the Journal of Internal Medicine, found that 1.5 women in 100 who reported they had the highest exposure to ultraviolet light were found to have died during the two decades, compared with three in 100 for women who said they had avoided sunbathing.The avid sunbathers had a significantly lower risk of death from cardiovascular disease and other conditions that were not related to cancer, the research explains.Dr Pelle Lindqvist, the epidemiologist who led the study, says the research also found that, “Non-smokers who avoided the sun had a life expectancy similar to smokers in the highest sun exposure group, indicating that avoiding the sun is a risk factor for death of a similar magnitude to smoking.”Dr Richard Weller, senior lecturer in dermatology at Edinburgh University, last year published a report in the journal Maturitas warning that older people in particular need to get into the sun more. “Advice on healthy sun exposure needs to be reconsidered,” he urges. “The older population are particularly sun-deprived as shown by low blood levels of vitamin D and lack of outdoor activity.”He adds that there is a reduction in cardiovascular disease and deaths from all causes with increased sun exposure. Two years ago, Dr Weller’s team established that exposure to sunlight may lower people’s blood pressure and thus cut their risk of heart attack and stroke. This benefit has nothing to do with vitamin D. Instead, it is due to the fact that when our skin is exposed to the sun a compound – called nitric oxide – is released in our blood vessels which in turn lowers blood pressure by causing blood vessels to widen.Dr Weller told Good Health, “It also appears that sunlight alters the way that our genes behave. Last year, Cambridge University scientists showed that the expression of 28 percent of our entire genetic make-up varies from season to season.” The Cambridge investigators reported in the journal Nature Communications that in winter we increase the activity of inflammatory immune-system genes – to combat infectious bugs – and in summer we increase the activity of anti-inflammatory genes.Chronic inflammation is linked to modern epidemics such as heart attacks, diabetes and cancer. Such inflammation results from our immune systems fighting infectious invaders. But this comes at a cost – as the tissue damage caused by long-term inflammation can itself cause disease. The Cambridge research indicates that sunlight may prompt our bodies to switch down the inflammatory response. “As well as nitric oxide and gene expression, I think there will be other factors that we have yet to discover,” says Dr Weller. “There is a correlation between more sun and less disease in a variety of conditions such as multiple sclerosis and atherosclerosis.” However, the causal link is yet to be shown.Scientists are discovering sunlight may even help us keep slim and healthy, according to studies by the Universities of Southampton and Edinburgh that kept mice on high-fat diets while they were exposed to the spectrum of ultraviolet light found in sunshine. The results show that ultraviolet radiation may suppress the development of obesity and the symptoms of type 2 diabetes.