Ultraviolet (UV) radiation from the sun can have both positive and negative effects on human health.
A small amount of UV radiation is essential in the production of vitamin D, however too much exposure to the sun can have serious effects on your skin and eyes. It is important not to be caught out by the sun so use our forecast, wear lightweight, light-coloured clothing, spend time in the shade and use a high factor sun cream with good UVA protection to protect yourself. Don't forget that UV rays from winter sun can actually be more damaging in alpine regions because you absorb both the direct UV rays from the sun and the diffuse UV rays reflected off of the snow.
British Association of Dermatologists has developed the World UV App in collaboration with the Met Office to provide the public with a free daily UV forecast for over 10,000 locations worldwide that can be accessed at the touch of your finger-tips.
The UV forecast identifies the peak strength of the ultraviolet (UV) radiation from the sun at a particular place on a particular day. UV rays can cause damage to the skin and can cause sunburn - which may lead to skin cancer.
Effects of the sun
Sunburn occurs when your skin is overexposed to UV radiation, usually from the sun's rays but also from sunbeds. Extreme sunburn can be very serious and all sunburn can cause serious ongoing health effects, however most people initially experience mild symptoms, such as hot red skin. Protecting yourself against sunburn is very important as excessive UV radiation directly damages the DNA in your skin cells. Often not all of the sun damage will be fully repaired by the body's defence system, so it will gradually cause skin ageing over the years and may lead to skin cancer.
The majority of skin cancer cases are caused by UV radiation either from the sun or sunbeds. It is one of the most common forms of cancer in the UK, with 11,770 cases of malignant melanoma (the most serious type of skin cancer) diagnosed in 2008 and more than 98,800 new cases of non-melanoma skin cancer (the less deadly type of skin cancer). However not all cases are recorded, there may be at least 100,000 new cases each year (Cancer Research UK Sunsmart).
Your risk of developing skin cancer does increase with age. However skin cancer is the second most common cancer among the 15 to 39 age group.
UV radiation can have both short and long effects on the condition of our eyes. We often protect ourselves against UV by using sunscreen or wearing protective clothing however do we consider what UV can do to our eyes? UV radiation from the sun or sunbeds can damage the eye's surface tissues as well as the cornea and lens. UV can burn the surface of the eye much like sunburn on skin. To protect your eyes from UV exposure wear good quality UV protective sunglasses.
Long term exposure to UV radiation can be more serious. Exposure to UV is a significant risk factor for cataract development which is the leading cause of blindness in the world. This is where damage is caused to the retina in the eye which is usually not reversible. Cataract appears to different degrees in most people as they age so protecting your eyes from sun exposure is important.
Your body produces vitamin D when exposed to UV radiation from the sun. Vitamin D helps to regulate the amount of calcium and phosphate in the body, both are needed to keep bones and teeth healthy.
The amount of time you need to spend in the sun to generate enough vitamin D varies from person to person. People can often generate enough vitamin D by spending just a few minutes in the sun. This means people can take the necessary precautions to protect themselves from burning and reduce their risks of developing skin cancer whilst still enjoying the health benefits from sunlight.
At altitude there is less atmosphere to filter UV rays. Snow reflects around 85% of the sun's UV rays so you may burn in unusual places. Look out for the underside of your chin and your ears in particular. Up to 80% of the sun's UV rays penetrate light clouds, and what gets through can reflect back and forth between the clouds and the snow. So even if it's cloudy it's important to protect yourself.
Effects of UV radiation on the eye
Diffused UV rays reflected off of the snow can mean that whilst participating in winter sports you are subjecting your eyes to twice as much UV light. This is why it is important to wear polarised sunglasses/goggles to reduce the amount of UV light reflected by the snow reaching and damaging the eye.