How long does sunscreen protection last, and when should it be reapplied

 

How long does sunscreen protection last, and when should it be reapplied?

The duration of sunscreen protection depends on the Sun Protection Factor (SPF) of the sunscreen and other factors like sweating, swimming, and rubbing. SPF measures the sunscreen's ability to protect the skin from UVB rays, which are the ones responsible for causing sunburn. The higher the SPF value, the longer the protection lasts.

As a general rule of thumb, you can calculate the time sunscreen protection lasts by multiplying the SPF value with the time it takes for your unprotected skin to start turning red in the sun. For example, if you start to burn after 10 minutes in the sun without any sunscreen and you use an SPF 30 sunscreen, your protection should last for approximately 10 minutes x 30 (SPF) = 300 minutes (5 hours).

If you are in continuous exposure of sunlight for last 2 hours then you should keep on reapplying it. It also depends on the type of sunscreen you are using if it's Spf 50 and above then reapply after 2 hours and if it is less then apply more frequently.

*However, keep in mind that this is just a rough estimate, and many factors can influence how long sunscreen protection lasts. These factors include:

1. Sweating: If you are sweating heavily, the sunscreen can wear off more quickly, reducing its effectiveness.

2. Swimming: Water can wash off sunscreen, so if you're swimming or engaging in water activities, you'll need to reapply more frequently, even if the sunscreen is labeled as water-resistant.

3. Rubbing or towel drying: Any activity that involves rubbing the skin or towel drying can remove the sunscreen from your skin.

4. Intense sun exposure: If you are exposed to intense sunlight or UV rays, sunscreen may not provide full protection for the entire duration based on the SPF calculation.

*To ensure adequate protection, it's generally recommended to reapply sunscreen every two hours, especially if you're outdoors, sweating, or swimming. If you're using a water-resistant sunscreen, it's still a good idea to reapply after getting out of the water, as water-resistant doesn't mean waterproof.

*Remember to apply sunscreen generously to all exposed skin, and don't forget commonly missed areas like the ears, back of the neck, and tops of the feet. Sunscreen is an essential part of sun protection, but it should be complemented with other measures like seeking shade, wearing protective clothing, and using sunglasses to protect your eyes from harmful UV rays