Sun Protection - Basic Knowledge

The sun's rays have a broad spectrum. Rays with a wavelength of 280–400 nanometers are called UV rays. They can damage the delicate DNA in human tissue, and since the skin is the first organ they encounter, it is particularly vulnerable.

The shorter the wavelength, the more energetic the radiation. Rays from 280 to 320 nanometers are referred to as UV-B rays, and rays from 320 to 400 nanometers as UV-A rays. UV-B rays only penetrate the epidermis and can cause sunburn as acute damage and skin cancer as chronic damage. UV-A rays penetrate deeper into the dermis, causing no acute damage, but chronically they can cause massive damage to the connective tissue, i.e., to the elastic and collagen fibers, and can even lead to skin cancer. UV-A rays are the main cause of sun-induced skin aging (photoaging). It follows that good UV protection must always be directed against UV-B and UV-A rays.

1. By avoiding the sun
2. Through textiles that are impermeable to UV rays
3. Sunscreens with chemical or physical (mineral) filters. Chemical filters absorb UV radiation energy and convert it into heat. Physical UV filters such as titanium dioxide or zinc oxide reflect UV radiation.

1. Skin type
2. The skin’s habituation to the sun
3. From the height above sea level
4. From proximity to the equator
5. Personal risk profile (personal or family history of skin cancer, number of moles)
6. Of the time of day and the season
7. The duration of the planned stay in the sun
8. From reflective objects in the immediate vicinity (e.g. water or snow)

There are different points of view on this. I don't think the routine use of chemical or physical filter systems in day creams is right. Chemical or physical filters should only be applied if you plan to spend a significant amount of time in the sun. If you drive to the office in the morning and back home in the evening, you don't need to apply sunscreen. However, I recommend always carrying sunscreen in your handbag, just in case.

If you plan on spending time in the sun, apply sunscreen 10-20 minutes before going out. If you plan on spending time in the sun early in the morning, you can also apply sunscreen first thing in the morning after your moisturizer. To avoid oversaturating the skin or overloading it with product, sunscreen can also be used instead of your moisturizer.

The rule of thumb is 2 mg of cream per cm² of skin. This corresponds to 40 grams for the entire body, or correspondingly less if only specific areas such as the face are to be protected.

The SPF always refers to UV-B rays because these redden the skin, cause sunburn, and therefore make the effectiveness of UV protection filters easy to measure. The SPF indicates by how much time you can spend in the sun before you turn red. Someone who turns red after 10 minutes in the sun without protection will only turn red after 100 minutes with an SPF 10. An SPF of 30 or higher is considered a blocker. Higher factors usually only provide marginal additional protection. An SPF of 100 is a marketing concept with no rationale for everyday use. The protective effect of a correctly applied SPF 30 is significantly higher than that of an incorrectly applied (too little) SPF 50. So, anyone who correctly applies a sunscreen with an SPF of 50 whose filters also provide good protection against longer-wave UV-A rays is considered effectively protected. Proper application means 2 mg of sunscreen per cm² of skin, equivalent to 40 grams of cream for the entire body (see above). However, effective protection does not exempt you from the points listed above, which must be considered every time you spend time in the sun.

When exercising (sweating) or after swimming, you obviously need to reapply appropriate sunscreen. This is common sense. There are no so-called water-resistant sunscreens. Such labels are not rational. It's also important to know that repeated application of sunscreen does not increase the SPF. So, if you apply SPF 20 twice in a row, you obviously won't get SPF 40 protection.

1. Get out of the sun
2. Apply cooling and soothing light lotions or, in the case of severe sunburn, short-term cortisone creams
3. Possibly internal pain-relieving or anti-inflammatory medication (e.g. aspirin or ibuprofen)
4. If necessary, medical care and subsequent skin checks to exclude or detect significant skin damage at an early stage

That's right. Effective UV protection prevents the skin's own production of vitamin D, which is stimulated by UVB rays. Therefore, anyone who doesn't take the opportunity to spend short, unprotected periods outdoors on a regular basis, and who doesn't consume significant amounts of vitamin D (e.g., milk, eggs, butter, fish), should have their vitamin D levels measured. If levels are too low, they should definitely take a vitamin D capsule once a week.

Octocrylene is a commonly used UV filter. Sunscreens containing octocrylene should not be used for more than one season, as octocrylene can decompose over time into potentially carcinogenic benzophenones. Some South Pacific states, such as Palau, have banned octocrylene entirely because it can potentially damage coral reefs. Octocrylene degradation products are also likely to have damaging effects on the endocrine system.

Oxybenzone and octinoxate, commonly found in sunscreen products, can harm coral reefs. To protect fragile marine ecosystems, the US state of Hawaii passed a law banning the sale of sunscreens containing these ingredients, effective January 1, 2021. Octocrylene will be added to the list of prohibited ingredients on January 1, 2023. Sunscreen products free of these ingredients will be labeled "Coral Reef Safe."