If you are exercising, it would be best to use a sunscreen with an SPF of at least 30 and reapply at least every two hours or after sweating.
15 and up
It is proven that people with light skins, are best protected when using a SPF 50 sunscreen and upwards. Sunscreen has SPF ranging from 8, all the way up to 70. Depending on your skin tone, it is better to be too careful by protecting with a high number SPF.
15;90
15;90
500
Assuming the question is asking about sunscreen SPF, it stands for sun protection factor. This is put on sunscreen bottles to show the consumer how strong the sunscreen is.
To calculate the Sun Protection Factor (SPF) for sunscreen products, you divide the amount of time it takes for skin to burn without sunscreen by the amount of time it takes with sunscreen. For example, if it takes 10 minutes to burn without sunscreen and 150 minutes with sunscreen, the SPF would be 150/10 15.
No. SPF 30 lets in 1/30 of burning UV rays, while SPF 50 lets in 1/50. Adding the two together is pointless and would not result in high levels of skin protection.
A million SPF
The SPF in the sunscreen plays no role in how many hours you can go without reapplication. If you need to quickly reapply your sunscreen after any water or exercise activities I highly recommend looking for a different brand. The Coppertone brand that I use, needs to be reapplied once every 8 hours even after sweating or water play activities.
The SPF number in sunscreen indicates its level of protection against UVB rays, which cause sunburn. The higher the SPF number, the greater the protection. For example, SPF 30 blocks about 97 of UVB rays, while SPF 50 blocks about 98. This means that a higher SPF number offers more sun protection.
It does. The higher the SPF, the higher UV protection it contains. Let's say you have a sunscreen with a 30 SPF and one with 60, the one with 60 offers more protection.