Sunscreen: need to know
The fact that over-exposure to the sun can be harmful has been well-publicised. A multitude of authorities, including Cancer Research UK, the Department of Health and the British Association of Dermatologists, recommend the use of sunscreens as part of "sun safe" behaviour. Visit SunAwareness to find out more.
But how much do we understand about what sunlight actually does to our skin and how sunscreens help combat its effects?
About the sun
The light from the sun has a strong effect on mood and we know that people feel better when the sun shines. In particular, those suffering from Seasonal Affective Disorder (SAD) show an improvement in the summer months. Sunlight also acts on the skin to produce vitamin D, which is essential for good health, in particular to maintain healthy bones.
Most of the damage from the sun comes from UV (ultra violet) rays - UVA and UVB.
UVB rays penetrate into the outer layer of the skin and damages the cells resulting in inflamed skin or sunburn.
UVA rays penetrate more deeply causing direct damage to the skin's supporting tissues, which contributes to the signs of skin ageing.
Both types of rays are attributed to causing different skin cancers, including malignant melanoma.
The video below uses UV light to show how the sun sees you:
Sunlight also contains UVC rays, but these are completely absorbed by the upper atmosphere and therefore do not pose a problem for us.