That the sun damages your skin is not news.
There are two main ways in which sunscreens work either by physically
blocking out the rays or by chemically absorbing them, dissipating
the UV energy as heat. Chemical sunscreens include benzophenone and
octyl methoxycinnamate, while titanium dioxide and zinc oxide provide
physical barriers, actually reflecting the rays. The main difference
is that the physical ones tend to leave a whitish color on the skin
(or very white, pink or green if you choose the cricketer or snowboarder
look) but they are generally better for sensitive skins. Using a cream
that contains both will give better protection, as different chemicals
work best in protecting from different ends of the spectrum of light.
The SPF (sun protection factor) of a cream refers only to its protection from UVB rays (the 'burning' ones), not the OVA (longer-term, 'ageing' rays) and gives you an idea of how much extra time you can spend in the sun without burning.
So if you usually burn after 20 minutes, an SPF 20 would protect you for 20 X 20 = 400 minutes (6 hours 40 minutes). However, it's now generally agreed that you should use at least an SPF 20 to protect yourself from skin damage, especially as you may not know exactly how long you take to burn or the effect of the environmental conditions (such as sun strength, altitude, etc).
Newer chemicals such as Parsol 1789 (chemical name: avobenzone) provide good protection from UVA rays. Better sunscreens also contain antioxidants, which protect the skin by mopping up oxidants as well as improving your immune defences.
Make sure you use enough sunscreen and in good time rubbing in a tiny amount half an hour after you've been out in the sun and have a sweaty sheen over your skin is going to make the cream more or less redundant. But remember, also, that the beach is not the only place you are exposed to the sun - just walking around on a sunny day puts you at risk of sun damage. And it's never too late to protect yourself. Even if you feel you could not do yourself any more harm than you have already done over the years, damage is cumulative so any protection is worthwhile.
If you do overdo it in the sun and get burnt, smother yourself in aloe Vera gel or calamine lotion, and later use a good moisturizer. It's really too late for much skin rescue to be done - but if you are taking a good antioxidant supplement, you are at least doing some good from the inside.
As with any products, not all sunscreens are equally good. Research has shown that chemicals found in some sun creams may actually pass on excess energy from the sun's rays into the skin, where it damages DNA. These chemicals are Padimate0, PABA-O or Escalol 507, says Dr John Knowland from Oxford University. The research was done in test-tubes, so it has yet to be discovered whether the same effect takes place in humans. Norwegian scientists have recently shown a common sunscreen ingredient, octyl methoxycinnamate, to be harmful to the skin especially when it is exposed to UV rays. |
