What You Should Know About Sun Exposure and Sunscreen

Updated: Jun 4


Busting fact and fiction when it comes to daily health tips, Dr. Bahareh outlines some of the most important things to keep in mind about your skin health.


Although the topic of sun exposure and skin cancer is overemphasized, the public actually knows very little about SPF, UV rays and sun protection. Even I needed some clarification on the matter, so I interviewed a friend who is in his dermatology residency to answer a few questions.


Understanding SPF

SPF stands for Sun Protection Factor, it is a multiplication factor that estimated the theoretical amount of time you can stay in the sun without getting sunburned compared to not wearing any sunscreen. It is thought that a higher SPF blocks out more rays, and this is true, but there is a point of diminishing returns. You also have to keep in mind that the higher the SPF the more chemicals you are exposing yourself to. Furthermore, SPF itself protects against UVB, its the ingredients like Zinc and Titanium Oxide which offer UVA protection.


There are many factors that can alter the effectiveness of sunscreen. Generally it is recommended to apply SPF creams about 20 minutes before sun exposure. Contrary to popular belief, you actually don't want to rub the cream into the skin to a point of invisibility, its preferable for the cream to sit on top of your skin. Since this would leave an unfashionable layer of white substance over the skin, it's often not ideal if you want to stay cosmetically elegant. As it turns out, in order for SPF to be effective, it needs to be applied at a thickness of 2mg/cm². There is some speculation about whether applying thinner amounts of a higher SPF cream ie 60 or more will result in about the same level of protection as a thicker layer of an SPF 30 cream. Up to about the SPF of 50, UVB protection is maximized, after 50 a very minimal increase in protection is noted. At about an SPF of 30 we see 97% coverage of UVB rays. For individuals with skin conditions that make their skin more susceptible, an SPF cream of 100 is recommended.


What is a tan?

A tan is when the skin has higher pigmentation as a result of overactivity of the melanosomes in melanocytes (skin cells) to create something called melanin. This is a protective mechanism of your skin against the suns rays.




Tanning Right!

We all know sunburns are not a healthy outcome; as with an increase in number of sunburns, comes an increased risk of skin cancer, though there is also a genetic component making some people have a higher likelihood. This has to do with changes in the transcription and translation of DNA during rapid cell turnover which also contributes to aging and undesirable wrinkles, a sign of aging. The biggest unfortunate myth about tanning, is that people wrongfully assume that one cannot tan while wearing sunscreen, and forgo the protection to have a tan. Wearing sunscreen the way the general population does (rubbing it in to skin) is protective against UV rays but up to a certain extent (as in never 100%). However, this is sufficient enough for us to avoid large doses of UV exposure at once and prevent sunburns. Wearing sunscreen will allow for you to be able to get a tan incrementally, with repetitive sun exposures, over days. Although this is a slow process, its actually the most effective way. Here's why:


- Tanning incrementally means you wont get a sunburn which will peel and leave you without a tan sooner than later while increasing your risk of skin cancer.


- For individuals whose skin is not generally exposed to the sun throughout the year, who end up taking a short vacation to a tropical location and spend long hours in the sun (even with the use of sunscreen with SPFs of around 40), are more sensitive to cellular free radical damage, than if they were to be exposed to the sun on and off over the year. If this form of sun exposure leads to a sunburn, this poses to be more of a risk for melanoma and BCC (basal cell carcinoma) skin cancers. Body segments that are generally exposed to the sun throughout the year like the face and arms, (compared to the chest, abdomen or back) have a decreased risk of melanoma but not BCC and squamous cell carcinoma (SCC). The individuals melanosomes that get more frequent sun exposure are photohardened. In summary, Cumulative sun exposure (as opposed to sudden), decreases melanoma risk but would not be favorable for BCC and SCC (squamous cell carcinoma). This is why we typically see SCC on the head and neck as these are the areas with the most cumulative sun exposure.


Tips for avoiding excessive sun exposure and general guidelines:

1) Wear a broad hat or light pool side wear to cover your body while staying cool if you don't want to get excessive sun exposure.

2) Wear the highest SPF you can find without spending more for SPFs that are higher than 60 due to diminishing returns.

3) Generally an SPF of 40 is great for slowly building a tan while protecting your skin, although the standard seems to be 30. 4) Remember that having the cream sit on the skin is what protects you from sunburn as opposed to a rubbed in invisible cream or spray. And remember to reapply if you are sweating or going in and out of the water.

5) Avoid tanning salons! It is not healthier to go to a tanning salon once a month for that "base coat" everyone talks about getting before the summer sun. Tanning beds are UVA only and penetrate deep into you skin and still cause cell damage and skin cancer.

6) There IS a difference between people of varying skin color pigments. Generally the darker you are the more protected you are as the melanin is there ready to protect you.

So you accidentally got burnt. Its sore, achy and hot. If extreme, it might be a good idea to take a low dose NSAID to decrease pain and inflammation, while adding on the following:

1) Drink PLENTY of water. Your skin barrier is compromised and you will lose a lot of heat and thus water. Also keeping hydrated helps the skin heal faster.

2) Avoid clothing over the area or sheets at bedtime. You would have figured this one out on your own as its pretty painful.

3) Aloe vera gel. Keep this gel in the fridge and apply a thin layer over the burn. Try to get a clear gel (non that have added dye that make them green). Reapply as needed. I generally find it soothing to rinse some cool water over it when the gel dries out or before reapplying a new layer.

4) Avoid any commercial lotions as the added perfume and chemicals can irritate the skin and cause pain. I would try to go with the most natural cream possible after a day or two of using the Aloe gel like "Burt's Bees Aloe and Linden Flower After Sun" cream. If you cant get this, coconut oil is always a great choice and you can begin using this interchangeably with the Aloe gel, preferentially over the Aloe gel once it dries.

























Bahareh Moshtagh, ND, 2019

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