Tag Archives: skin cancer

Sun Poses Long-Term Dangers to Outdoor Workers

By Dr. Donald Bucklin

With the summer and its heat approaching, almost everyone will be out in the sun more than they were during the winter.

For 9 million Americans, being outside and in the sun is not just for summer fun – it’s a part of their job.

Workers in farming, landscaping, construction, recreation and even postal workers will spend hours in the sun – and consequently be exposed to potentially harmful levels of ultraviolet radiation.

Working in the Heatphoto © 2011 MSDSonline.com | more info (via: Wylio)Ultraviolet radiation, and specifically UVB, is the main environmental hazard to the outdoor worker. Most workers’ shifts include the peak intensity hours of UV exposure – 10 a.m. to 2 p.m. Since this type of radiation, UVB, easily penetrates clouds, it can reach worrisome levels even on days where little sun is visible. It easily passes through glass and can be reflected into areas of apparent shade.

UVB penetrates through the tough, dead outer layers of skin, into the replicating layers. It is there that it interacts with the living tissue, not entirely in a negative fashion – UV radiation on unprotected skin produces Vitamin D. Many believe, and there is some evidence to back it up, that there are anti-cancer properties in this potent antioxidant vitamin.

But radiation on living tissue also has a biologic cost. UVB radiation causes DNA damage and is officially listed as a carcinogen. This damage is cumulative. Ultraviolet radiation and skin cancer share a similar relationship to that of cigarette smoking and lung cancer. According to the Skin Cancer Foundation, those who work outside are twice as likely to contract skin cancer as indoor workers.

To protect workers from this hazard, we need to reduce the dose of UVB radiation.

The obvious solution for employers is to instruct workers to avoid sun exposure and seek shade when available. When possible, employers can rotate or stagger work shifts so that employees spend less time working during the sunniest parts of the day.

While the suggestion that people wear long-sleeve shirts during high temperature periods usually is greeted with derision, in fact there are a variety of new fabrics with high Sun Protection Factor values that are light weight, breathable and durable.

One of the oldest fabrics, cotton, has long been recognized for its skin protective value in the hottest climates. Cotton long-sleeved, loose-fitting shirts and pants, and broad-billed hats are some effective clothing options for outdoor workers. In dry climates, the fabric actually soaks up sweat and is an effective evaporative cooler.

Sunblock provides UV protection, but the level of protection is almost universally overestimated.

The most common error people make is using high Sun Protection Factor, sweat-proof sunblock and applying it only once. Sunblock generally loses effectiveness after about two hours due to sweating, the friction of clothing and deterioration due to sunshine. And too often, too little is applied. An ounce is recommended to get advertised protection. But remember, sunblock isn’t “liquid shade.”

These common sense protective measures can help safeguard you and your employees year round, but particularly during the summer months when, in most parts of the country, exposure to UVB radiation is highest. With awareness and a few simple steps, we can help workers avoid the short-term sting of a sunburn and the long-term consequences of too much sun exposure.

Sunshine 101

Summertime. The kids are off, the pool is warm and the sun is working overtime, at least if you live in Phoenix, Arizona. I daresay we may very well be the sunshine capital of the country. Our newspapers don’t list minutes of peak sun exposure to sunburn – we list seconds. Perhaps a bit of an exaggeration, but we know sunshine in the desert.

Before we get into the latest anti-aging/fountain of youth/magic sunblock, we need to talk about sunburn a bit.

The sun is a great big natural nuclear reactor up in the sky. Interestingly enough, the earth quakes (sun quakes) and tidal forces on the sun are literally off the Richter Scale, but the sun seems to tolerate them and should for a couple more billion years. The sun puts out radiation that they don’t make sunblock for, but by the time that radiation reaches earth, it has been reduced in intensity about 10 zillion percent. What is left is a mixture of X-rays, ultraviolet, visible light and infrared (heat) radiation. Most of the X-ray radiation is dispersed in the atmosphere. We are big fans of the visible and infrared radiation (think of a lizard sitting in a sunbeam). The ultraviolet we deal with less elegantly than the infrared.

sun shadephoto © 2007 .D.B. | more info (via: Wylio)

Ultraviolet light is broken up into 3 kinds – A, B and C. They do this to confuse people and make it seen complicated. UVA is the closest to visible light; it passes most easily through the atmosphere and won’t give you a sunburn. UVA is used in tanning beds and photo therapy. Photo therapy is when you go to Hawaii because you’re depressed (and try to deduct it as a medical expense).

UVB is shorter and higher energy. The ozone layer absorbs much of it, but we get enough at the surface to still get a pretty good sunburn. UVC is entirely absorbed by the atmosphere, and a good thing too, because it is germicidal and could wreak havoc with the microbes and ecology of the world – not to mention, you could watch your skin age.

The problem with ultraviolet radiation is it damages the skin. Excessive exposure over a short time results in the well known sunburn. This is a first-degree burn to sun-exposed skin. Anyone who has ever had one can appreciate just how much skin you have. It’s the largest organ on the body, and it is well supplied with nerves, particularly pain fibers. Hydration and ibuprofen are the way to go with the usual sunburn. A really severe sunburn needs hospitalization with IV hydration and serious pain meds.

But skin is damaged by sun exposure, even if there is no visible sunburn. Ultraviolet radiation penetrates surprisingly deep into tissue, damaging cellular DNA and elastin. DNA damage is usually repaired successfully by healthy cells. Rarely, the cell is repaired incorrectly but goes on and multiplies. We call that cancer.

UV radiation also breaks down the elastin in the skin. The elastin gives the skin its tone and support. Damage to the elastin leads to premature wrinkling and aging of the skin – a fate worse than death, according to some.

Sunblock is a recent development in society and has become an essential accessory on the equipment list for outdoor activity. There is little doubt it is generally effective at lowering UVB dosages, which reduces the more common kind of skin cancer and skin aging. Beyond that, sunblock is widely misunderstood. When was the last time you read the instructions on a sunblock bottle? Although it is counterintuitive, it doesn’t block the instant you smear it on. We think of them as paint. Smear them on and instant shade. They actually bind with elements in the skin to become effective. This takes time. In general, sunblock needs to be applied 15 or 20 minutes before sun exposure for peak effectiveness.

Then there is that whole Sun Protection Factor (SPF) number. There is a complicated formula to calculate the protective value of a sunblock. I have been known to stand in front of the sunblock display and carefully consider my outdoor activity and which to buy among 15 different brands, claims of waterproof/sweat proof/anti-aging and SPFs from 15 to 60. A frustrating experience and a waste of time. Buy your favorite smell, nicest bottle or least expensive as long as the SPF is 15 or greater.

The SPF factor is almost irrelevant. The SPF value of your sunblock is the least important ingredient in whether you get a sunburn. The dirty truth: sunblock only protects you for about 2 hours. Sunblock loses effectiveness with time, water, sweat, dirt and sun exposure. If you apply SPF 15, you will block about 90% of UV radiation for 2 hours. If you apply SPF 50, you will block 95% of UV radiation for 2 hours. After 2 hours, you are on your own. High SPF numbers wash, sweat and bake off just as fast as low SPF numbers. You really can’t get longer protection from higher SPF numbers.

The next common sunblock operator error is not using enough. Too thin of a layer will not protect you fully. That means you need to use an ounce. What is an ounce? Fill up a shot glass. That’s a lot of sunblock!

Sunblock also has an expiration date on it. Don’t count on full 2-hour protection if the bottle is expired.

Keep in mind, that the best sunblock is not portable shade. It is hard to beat shade. There is a reason the outdoor workers in Phoenix wear long pants, long-sleeve shirts and hats, even in the summer. Clothing does not lose its SPF factor for years. You can even be one of those funny people who carry umbrellas on sunny days when shopping.

Summertime is a great excuse to be outdoors doing active, fun things. A little preparation will allow you to avoid a sunburn and play another day.

Take care,

Dr. B

Sunshine – Friend or Foe?

Sunshine is necessary for human survival and the survival of every other plant and animal on the planet. But are we supposed to spend time in the sun or just enjoy the secondary benefit – that our planet isn’t a frozen ball of rock in deep space? The pendulum of medical opinion on sun exposure seems to swing regularly. We have all met someone with a deep tan who looks like a human Shar Pei at 45.

The case against spending time dozing in the sun, like a lizard, is strong. Sunlight has a lot of ultraviolet radiation. This radiation penetrates the skin and damages the DNA. Damaging DNA is a bad thing to do because sometimes the cells will die, and occasionally they will turn cancerous. Skin cancer is clearly associated with sun exposure. Unfortunately, the time your skin is most susceptible to sun damage is before you are old enough to read the sunscreen bottle. If that isn’t bad enough, ultraviolet radiation also breaks down the elastic elements in the skin. Destroy enough elastin, and you resemble that Shar Pei.

For the last 20+ years, the entire medical community has been yelling, “Stay out of the sun!” Then a funny thing happened – we started looking at vitamin D and cancer.

A bit of background. Vitamin D is made in the human body by sun exposure on your skin. The more intense the sun exposure, the greater the level of vitamin D produced. Doctors have known since the Mayflower that low vitamin D levels cause rickets. In modern times, most of us have seen skin cancer but never a single case of rickets, thus the advice, “Avoid the sun.”

About 10 years ago, scientists were studying sun exposure and deaths due to skin cancer. This was a pretty detailed and serious study. They found the expected modest increase in the number of skin cancer cases but a substantial decrease in deaths from all causes. Some head scratching ensued. The scientists then decided to measure vitamin D levels by areas of the country and compare them to various causes of death. They found people in sunny places like California and Arizona had less cancer, heart disease, multiple sclerosis, rheumatoid arthritis, and even Alzheimer’s disease. Places like Minnesota and North Dakota had less skin cancer but more of everything else.

Vitamin D acts as a hormone in the body and has its fingers in numerous biologic reactions. The current thinking is vitamin D protects against a number of different diseases. Unfortunately, vitamin D supplementation is a recent development. It hasn’t been around long enough to actually prove protection against all these various diseases (from cancer to Alzheimer’s).

Today I would tell you a modest dose of sunshine on a daily basis is a good thing. You should live longer for it. Move to Arizona or Florida; become a nudist. If that doesn’t fit in your life plan, you might just want to stick with vitamin D supplements.

- Dr. Don Bucklin, National MRO – a.k.a. “Dr. B”


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