Have you ever wondered what SPF means or if you could use last year’s sunscreen? Read on……..
There is much controversy as to whether the sun is good or bad for you. Life is often about a healthy balance and in my June blog I will cover 10 health benefits of moderate sun exposure.
One thing, however, everyone should be aware of is that sunburn is definitely something to be avoided!
1. What does SPF mean?
Sun Protection Factor, is a measure of how well a sunscreen will protect skin from UVB rays, the kind of radiation that causes sunburn, damages skin, and can contribute to skin cancer.
If your skin would normally burn after 10 minutes in the sun, applying an SPF 15 sunscreen would allow you to stay in the sun without burning for approximately 150 minutes (a factor of 15 times longer). While that seems easy enough, the formula doesn’t necessarily hold true when you’re dealing with SPF numbers that are higher than 30. SPF is actually a measure of protection from the amount of UVB exposure and it is not meant to help you determine duration of exposure, as this depends on skin type, intensity of sunlight and the amount of sunscreen used.
The SPF (Sun Protection Factor) scale is as follows:
- SPF 15 blocks 93% of UVB rays
- SPF 30 blocks 97% of UVB rays
- SPF 50 blocks 98% of UVB rays
So, one way of looking at this is that SPF 30 sunscreen only gives you 4% more protection than SPF 15 sunscreen. Sunscreens with really high SPFs, such as SPF 75 or SPF 100, do not offer significantly greater protection than SPF 30 and mislead people into thinking they have more protection than they actually do.
2. How much sunscreen should you use?
For best protection, experts recommend using a minimum SPF sunscreen of 15. Applying the proper amount is very important and as a rough guide that is 2 tablespoons for full body coverage. Most people under-apply sunscreens, using ¼ to ½ the amount required. Using half the required amount of a factor 30 sunscreen only provides an effective SPF of 5.5!
3. How often should you reapply sunscreen?
There are several factors to take into consideration like your skin type and the time of the day but general consensus is about every 2 hours and after swimming or strenuous exercise. If you have very fair skin you should re-apply more often.
4. What is the difference between UVA and UVB?
UVA rays penetrate deep into the skin’s thickest layer. Unprotected exposure can lead to premature skin ageing and wrinkling.
UVB rays will usually burn the superficial layers of your skin. It plays a key role in the development of skin cancer.
When choosing your sunscreen make sure it’s a sunscreen that offers both UVA & UVB protection.
5. Can you use last year’s sunscreen?
Sunscreen has a shelf life of two to three years, as long as it’s not stored at high temperatures or in direct sunlight. Make sure you keep sunscreen in a cool or shaded place at all times. After this time sunscreen should be discarded. Not all sunscreens have a “use by date” so a good idea is to write the date you purchased your sunscreen on the bottle.
Enjoy your time in the sun making sure it gives you a healthy glow, nothing more dramatic!