the upside of sun exposure

by Kate Shapland

At this point in the summer most bathrooms and washbags are awash with sunscreen – all factors at the ready for holiday and stay-at-home protection against the sun. Quite right too, for there’s no question that ultraviolet (UV) rays can be a danger to skin – they’re a known carcinogen. But sunlight is a mixed blessing because moderate exposure to it can also benefit health, making stronger bones, better sleep, mood and immunity.

As the evidence for this grows, many experts – including the Cancer Council Australia – are rethinking their rigid sun-avoidance advice. The National Academy of Sciences recently assembled an international group of medical experts from different fields to discuss sun safety, and their published report concluded that “although the harms associated with overexposure outweigh the benefits, the beneficial effects of ultraviolet radiation (UVR) exposure shouldn’t be ignored in developing new sun safety guidelines”.

In other words, it might be said that if you continuously shield every inch of yourself with sunscreen you could be missing out on the upside of those rays.

Bone health & beyond

The best known benefit of sun exposure is vitamin D synthesis, which occurs in the skin in response to the sun’s UVB rays. And vitamin D is absolutely essential to promote absorption of calcium, the mineral that helps keep bones strong.

And sunlight may play other roles in promoting good health: the research is ongoing, but so far studies suggest that UV exposure might lower blood pressure (which helps to protect against heart attack and stroke), curb appetite and reduce the risk of obesity, type 2 diabetes, and possibly certain auto­immune diseases.

Sunshine may even be linked to longevity. One study that monitored nearly 30,000 Swedish women for about 20 years found that those who spent more time in the sun lived six months to two years longer than those who racked up less sun exposure. More research is required to replicate this work, but if it’s a real effect, it’s a very impor­tant find”.

However, the UVB rays that help our skin produce vitamin D are also the same type that cause sunburn, and getting burned is a major risk factor for skin cancer. That’s why it is so vital to find the right balance.

Short, sharp sun stints?

In the summer it takes only about 10 minutes a day of unprotected solar exposure on a small area of skin to produce around 5,000 IU of vitamin D, which is enough for most people – even the elderly, who have a slightly reduced capacity to make vitamin D – to maintain normal blood levels.

But for some people, 10 minutes might be too long; for others, too short. How much is enough is hard to quantify since skin pigmentation affects how much UV radiation your skin absorbs, but it’s thought to be much less than you need to get a sunburn.

It’s important though, to always err on the side of safety. You don’t even want your skin to get a little pink, because that signifies damage and even that amount of exposure/damage is enough to outweigh the benefits of that session of exposure.

Keep in mind too that the amount of time you can spend in the sun without burning on a particular day doesn’t reset to zero with subsequent time outside. So if you know that you can spend 15 minutes in the sun without your skin turning pink or burning that should be your total limit for the day – whether it happens in one, two or three goes.

Let in the light

Perhaps the message is then that when you are actively exposed to the sun – so in your bathing suit at the beach – use a sunscreen over your entire body and face. But when you are merely venturing outside on a sunny day, you can perhaps get away with sunscreen on your face and hands (they’re always getting sun and are at high risk for skin cancer, wrinkles and brown spots), wear a broad-brimmed hat and sunglasses, but expose what you can of your arms and legs. And if you are particularly sun-sensitive (you might have had skin cancer or you take a medication – such as certain diuretics and anti­depressants – that increases your risk of sunburn), talk to your doctor before going without sunscreen even in isolated areas.