2012-05-29

Save your skin

In the United States, we recently took pause on Memorial Day [Wikipedia] to recognize and remember the men and women of service who have given their lives and life’s work to preserve the lives or life-work of others. For many, Memorial Day also marks the typical start of the Summer vacation season. The increase in outdoor activity, coupled with the longer Summer day-lengths [“Survival Guide: Tell time using the Sun or Moon” - INDY Blog], means more time under that bright ball of fusion: the Sun.

There’s a lot of energy radiating from all that solar activity; most of that energy is wonderfully beneficial, bringing light and sustenance to our world, but some of that energy can also be rather harmful. Today, I’m going to discuss both the costs and the benefits, so that you’re better prepared to embrace the Summer months.

First, let’s talk about the energy coming from our star, the Sun [“Sunlight” - Wikipedia]. The large majority of the solar spectrum is in the range of radio waves, infrared, and visible light. The remaining bit is made up of ultraviolet and X-rays.


Source: "Solar Spectrum" - Wikipedia

As I said, radio waves, infrared, and visible light are very common, in fact, you see visible light every day! The wavelengths of these particles are long enough that they are harmless, except to the most sensitive of receptors (e.g. your eyes). It’s really the high-energy short-wavelength radiation which we need to be concerned about, so let’s take a look at those types now.

You may have heard of Gamma rays, that highly energetic form of electromagnetic radiation which can ionize atoms and, therefore, cause damage to biological organisms at the cellular level. Scary stuff, right? Well, lucky for us, the Gamma rays generated by our star’s solar fusion are processed into lower energy radiation before they even reach the surface of the Sun. Even so, other phenomena do generate Gamma rays, but typical exposure is extremely rare and in miniscule doses. Better still, our atmosphere does an excellent job of absorbing and reflecting these and other high-energy particles, such as X-rays.

Let’s take a look at what is left in our spectrum of sunlight: ultraviolet radiation. Ultraviolet (UV) radiation falls between the spectrum of visible light and X-rays, hence the name “ultra-violet” “extreme violet”. UV light is categorized into three types: UVA, UVB, and UVC. For the purposes of this article, let’s discard UVC (as that’s what our atmosphere literally does for us, it allows very little UVC to reach the surface of Earth). Instead, we’ll focus on how the remaining two types of ultraviolet light affect us on the cellular level; more specifically how they affect our skin.

All forms of UV light can damage and age the skin and cause cancer. Higher frequency UV radiation (e.g. UVB and UVC) can directly damage the DNA in our cells, causing mutations we call cancer. UVA indirectly causes DNA damage by exciting cells deeper within the body. Those cells may not be mutated, but they sure do misbehave in their excited state. However, you shouldn’t hurry to cancel your Summer vacation plans and shutter yourself into darkness. These same types of UV radiation play essential roles in our body’s natural processes.

That same skin-penetrating UVB triggers the synthesis of Vitamin D in our bodies. Vitamin D helps in the regulation of metabolism. Meaning, Vitamin D -- and other sun-generated vitamins and hormones -- are part of the process that tells your body whether to use the food energy (calories) you’ve consumed, store that energy for later (fat), and when your body should decrease its overall energy use (sleep). Some psychiatrists theorize that Vitamin D and serotonin influence mood and disposition. [“Seasonal affective disorder” - Wikipedia]

As with many things in life, we strive to find balance. Sunlight is “the only listed carcinogen that is known to have health benefits” [“Risks and benefits of sun exposure” - Wikipedia]. How can we minimize the risk of harm while receiving helpful benefits of the Sun’s light? This is where human technology and intelligence come in!

Sun protection has improved significantly since its invention. Sunscreen, in its most current form, can better withstand environmental conditions (e.g. temperature, moisture, etc.) and provide a better Sun Protection Factor (SPF). SPF, we find those numbers on bottles of sunscreen almost everywhere, but what do they mean?

The Sun Protection Factor (SPF) is a measure of protection offered by the sunscreen against UVB, which can cause sunburn. The true effectiveness of sunscreen depends greatly on a combination of factors: skin tone, amount of sunscreen applied (and re-applied), and the amount of sunscreen lost (absorbed into the skin or loosed from it by the environment and activity).

HOW TO FIND THE RIGHT SPF RATING FOR YOU
STEP 1: Determine your skin tone and “time multiplier”. Would you consider your skin tone light (10 minutes), intermediate (15 minutes), or dark (20 minutes)?
STEP 2: Multiply the SPF rating by the time multiplier found in STEP 1.
(SPF rating) x time multiplier
STEP 3: The result is the estimated time (in minutes) your skin will be protected from UVB.
Keep in mind that most people have the tendency to only apply half as much sunscreen as they should. So, you may wish to compensate for this by dividing your result by 2 or 3. Also, cloud cover can decrease your exposure to UV light, but it won’t eliminate it entirely. Additionally, reflective surfaces may increase your exposure (since you’ll get it from multiple directions). Finally, you’ll recall that wonderful atmosphere I discussed earlier, protecting us from some of those high-energy rays? Well, the higher your altitude, the less atmosphere there is protecting you.

The most important thing to remember in all of this is that it is up to you to protect yourself from harm. Remember what I said, all forms of UV can cause cancer. Be careful not to overindulge to the point where you take your skin from one extreme to the other. Meaning, if you have naturally light skin tone, you should avoid altering your skin to the point where its tone would be considered dark. The amount of aging and radiation that it would have to undergo to reach that level of melatonin would be rather unhealthy. Find the right balance and keep yourself safe and healthy.
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