You need to reapply sunscreen every 2 hours... How to properly block UV rays?

◆ Sun protection is essential even inside the car

Typically, the front windshield of a car is made of laminated glass that blocks UVB and UVA rays, but the side and rear windows are not. According to the American Academy of Dermatology, drivers are more likely to develop skin cancer on the left side of their face and body exposed to sunlight. In fact, 74% of patients with malignant melanoma had tumors on the left side. Therefore, even when staying inside the car, it is important to apply plenty of sunscreen. Wearing UV-protective sunglasses can reduce glare and also protect the eyes from cataracts.

◆ Sunscreen also needs to be reapplied every 2 hours

Sunscreen, whether SPF 30 or SPF 100, should be reapplied at least every two hours. SPF only indicates how much sunlight is blocked, not how long the protection lasts. The reason sunscreen only lasts for about two hours is because sunlight and moisture break it down, or some chemicals disappear. Additionally, not applying enough sunscreen is also problematic. Even if you use SPF 30, applying only one-third of the necessary amount will only provide the effect of about SPF 10.

◆ You should continue using sunscreen even as you age

Continuous exposure to sunlight remains dangerous even with aging. Typically, up to the age of 20, only 25% of lifetime ultraviolet exposure occurs, but it is important to continue being cautious about UV exposure after age 20. Especially if sunscreen was rarely or never used during childhood, using sunscreen becomes even more crucial. It is advisable to choose a broad-spectrum sunscreen that blocks UVB and UVA rays, which can cause skin cancer.

◆ No need to worry about vitamin D even when using sunscreen

Vitamin D obtained from sunlight is important for bone health and plays a vital role in immune function and muscle function. A small amount of UVB that passes through sunscreen is sufficient to help the body produce vitamin D. Levels can also be increased through diet. Foods rich in vitamin D include salmon, canned tuna, eggs, vitamin D fortified cereals, orange juice, soy milk, and milk.