UV exposure

How do you tan outdoors safely?
Tanned skin is damaged skin; to tan outdoors safely is a bit like smoking cigarettes safely. The more sun exposure you have, especially in bursts of exposure, the more dangerous it is.

There is no question that sunburns are harmful. They are directly related to skin cancers like basal cell carcinoma and melanoma.

If you got a sunburn, then you got too much sun.

What the sun actually doing to your skin?
Ultraviolet light from the sun can be divided into three categories, UVA, UVB, and UVC. UVC is the most dangerous, but does not penetrate the atmosphere and therefore poses no harm to us on the ground. UVA is the least potent and is the type of radiation used in tanning booths. UVA causes darkening of your skin within minutes, but this “tan” is short lived and offers no protection against sunburns. Of note, it is UVA that has been most implicated in melanoma skin cancers and in wrinkles and aging. UVA penetrates to the deep layers of the skin and over years destroys the elastin and collagen. See the purple blotches and paper thin skin on your grandfather’s arms? That’s UVA.

The amount of UVB is only 1/100th as much as UVA, but it is 1,000 times more erythemogenic (skin damaging). It is carcinogenic and is the radiation responsible for skin cancers such as basal cell carcinoma and squamous cell carcinoma. UVB, in contrast to UVA, causes your skin to develop a long term tan. It does so by damaging the DNA in the skin sending a signal to your melanocytes (pigment cells) to make more pigment. The result is a tan several days after your exposure. This type of tan is protective of your skin, but only at the expense of previous damage.

Tanning booths use mostly UVA with minimal UVB (UVB, like I said, is a clearly carcinogenic, and not a good product to sell); the resulting pigmentation will not protect you against sun damage.

Ultraviolet light is also essential for vitamin D synthesis. The darker your skin, the more sunlight you need to make vitamin D. Most people with fair skin need only a few minutes of exposure to their face and hands each day. The amount of vitamin D synthesized from sun exposure is highly variable and is not a good way to ensure you’re getting the recommended daily allowance.

The best way to get vitamin D? Just take a daily supplement.

What are the best hours to do it?
In the summertime you should avoid sun exposure from 10 AM to 2 PM.

What the minimum SPF you can get away with?
In summer, most people need a sunscreen with an SPF of 30 or higher. However, SPF is only half the story. SPF is a measure of the UVB protection only. A sunscreen with a high SPF might not be proactive against UVA at all. Starting this year, the FDA will now require that sunscreens be labeled with a star system to indicate what the UVA protection is as well. One star would represent low UVA protection up to four to represent the highest UVA protection available in an over the counter sunscreen product.

Most sunscreens quickly degrade after exposure to ultraviolet light; you must reapply after a few hours to stay protected.

How long can you be out?
When we advise patients to seek sun to treat certain diseases, such as psoriasis, it is usually just a couple of minutes of sun exposure a day. Now, that does not mean that you cannot be in the sun at all. It is just that purposefully exposing yourself to the sun can give a significant dose of radiation in a very short period of time. If you feel your skin burning, you’ve had enough.

Do you need to rotate frequently?
I can’t really answer this.


Always protect your face?
The vast majority of skin cancers are on the face. Wrinkles, brown spots, white spots, and scaly sun damage bumps are all found on the face. This is no coincidence; your face gets the most exposure to ultraviolet light. Billions of dollars are spent each year on Botox, laser treatments, and bleaching creams.

I have never had a patient over 40 say to me, “Gee I wish I had gotten better tans when I was younger.” The realty is: tan more now, see me more later. Or save yourself time and money -- always protect your face with a hat and broad spectrum sunscreen.