Blog 3: The Sun’s Dual Scale for Runners

By Stephen H. Paul, Ph.D.
Temple University

Like numerous issues in a healthy lifestyle, the largest star we can see can be our best friend, and then develop to become a deadly adversary. In our sport, the sun is important when training, racing, and all outdoor activities. From a medical perspective, the sun and its effect on athletes ranges the entire spectrum from beneficial to being injurious.

In a dialogue with a dermatologist the clinician can relate the reasons why the sun is vital to our health. In another exchange the “medicine man” encourages following the directions on the sunscreen container to protect the skin from the sun’s harmful rays. In fact, one very clever manufacturer with a chemistry background goes even further. The Blue Lizard® sunscreen bottles actually change colors when the radiation comes in contact with only the container. The contents inside when properly applied serve one of the major tools in protecting us. When athletes are outdoors, anytime from sun rise through sunset, the radiation continually bombards the ground and everything on it. Rain, snow, clouds, and fog reduce the radiation by roughly 20%.

The challenge is to avoid excess sun exposure that will avoid the sunburn leading to cancer and premature aging. It is almost impossible to avoid some or lots of skin tanning. Did you realize that the tanning function of the melanocyte skin cells is damage control? Those cells produce melanin.

Vitamin D is also called the sunshine vitamin or a pro-hormone because it is produced by the body as a response to sun exposure. You can get all the Vitamin D needed from the sun, certain foods, and/or Vitamin D supplements. The greatest danger from Vitamin D is when we are exposed to excessive radiation from the sun.

Can Vitamin D Cause Skin Cancer?

The answer is “yes.” It can cause numerous types that are a specific result of excessive sun exposure.


Cancer is a generic word for the group of diseases that result from abnormal cell growth. These cells may stay in one area or they can invade or spread to other parts of the body. The disease also causes general symptoms like tiredness and weight loss. When it impacts on one or more various body parts it USUALLY incorporates their names. This is how the “breast cancer” or “stomach cancer” comes into our vocabulary. For readers desiring additional information on cancer signs and symptoms go to:

When abnormal cells move a distance from the primary cancer site to another part of the body, those cells are known as a secondary malignant growth. Figure A shows the sites of metastases for common cancer types except for prostate cancer. This abnormal growth in the prostate solely occurs in males. If and when cancer cells exit the prostate gland they usually metastasize (spread) to the bones.

Figure B Illustrates how some cancers can spread to other site(s) in the body. This illustration shows how a hematogenous metastasis can create more than another tumor in the human body. Some cancer cells, known as circulating tumor cells, acquire the ability to penetrate the walls of lymphatic or blood vessels, after which they are able to circulate through the bloodstream to other sites and tissues in the body. This process is known as lymphatic or hematogenous spread.

Skin Cancer

Each exposure to direct sunlight on any area of uncovered skin adds to the damage received from birth. Left undefended, ultraviolet A (UVA) and ultraviolet B (UVB) will result radiation damage, could result in precancerous areas on our bodies called actinic keratoses (AK). These growths are common in fair-skinned individuals, runners who are frequently in the sun, as well as workers who jobs require them to be outdoors most of their working hours. AK starts to show up after years of exposure to the sun. If untreated, AK can progress to a solitary or supplementary skin cancers known as squamous cell carcinoma (cancer). New skin cancers like basal cell carcinoma and myeloma do not have to start with AK.  The Figure C drawing shows where squamous cells, basal cells, and melanocytes are located in different layers of the epidermis. The figure is just a representation of the skin.  A more realistic anatomy representation of the skin is in Figure D.

Squamous Cell Skin Cancer

Squamous cells are found in many places, and squamous cell carcinoma can occur anywhere squamous cells are found.

Most squamous cell skin cancers are found and treated at an early stage, when they can be removed or destroyed with local treatment methods. These cancers can be effectively removed by cutting out the tumor in conjunction with a small margin of normal skin. Small squamous cell cancers can usually be cured with these treatments.

Larger squamous cell cancers are harder to treat, and fast-growing cancers have a higher risk of coming back. Mohs surgery has the highest cure rate for these types of cancers that are larger than 2-cm (about 4/5 of an inch) across and/or poorly defined edges. This type of surgery is also used for cancers that spread along nerves, and for the genitals or the face.

In rare cases, squamous cell cancers can spread to lymph nodes or distant parts of the body. If this happens, treatments such as radiation therapy and/or chemotherapy may be needed. .

Basal Cell Skin Cancer

Basal cell carcinoma often occurs on areas of the skin that are exposed to the sun. This cancer appears as a change in the skin. It could be a transparent bump on the skin. This means that you could see a little portion through the surface. Tiny blood vessels could also be there. It could be a growth or a sore that will not heal. Prime areas are the head, face, ears, neck and arms. It appears less often on the legs and midsection. Most basal cell carcinomas are thought to be caused by long-term exposure to outside activities. Check the following site for additional information.

Myeloma Skin Cancer

Myeloma is the other form of skin cancer.  There is no difference between myeloma and multiple myeloma. Myeloma can occur on unexposed or exposed parts of the skin and can be deadly after short-term or continuing body exposure. The name Myeloma comes from the Greek Words for “myel” meaning marrow and “oma” meaning tumor. Myeloma are malignant (harmful, spreading) blood plasma cells that almost always occur in more than one area. Due to more than a single location and it is often called multiple myeloma.

This disease begins in the bone marrow. This is the soft, spongy tissue that fills the center of the bones. The bone marrow is where blood cells such as red blood cells, white blood cells, and platelets are made. Figure E illustrates the mechanism of how the blood stem cell produces red blood cells, platelets, and various white blood cells.

Patients with this cancer disease produce an exceptional amount abnormal plasma cells in the bone marrow. These cells multiply, building up in the marrow. Fewer platelets, healthy red blood cells, and white blood cells are produced. Red blood cells transport oxygen, nutrients, and other substances to all tissues of the body where they provide specific functions. White blood cells protect against inflammation, infection, and disease. Platelets form blood clots to help prevent bleeding. This buildup of myeloma cells can lead to various medical problems. These challenges include a reduction in blood cell formation, damage to the surrounding bones, organ damage, and problems with blood clotting and circulation as shown in Figure F.

Unfortunately, there are a voluminous number of risk factors and causes for multiple myeloma.  They include, but not limited to, the sun’s rays, radiation leakage from nuclear disasters, race, age, obesity, and toxic agricultural chemicals.

There is currently no permanent cure for the majority of multiple myeloma patients. However, it is a treatable disease and many patients are able to have meaningful lives for over a decade with an early diagnosis and utilizing the best available therapeutic remedies. These therapies encompass induction therapy (part of a standard set of treatments, like surgery followed by chemotherapy and radiation), consolidation chemotherapy to sustain remission, maintenance therapy radiation, and/or further surgery may be necessary in certain circumstances.

Taking Care of Your Skin

It is imperative to remember than cancer avoidance requires runners to follow a variety of pointers to minimize and hopefully avoid squamous, basal, and myeloma, weathered looking skin, and premature wrinkles. The easiest pointer to follow is to seek training areas where there is lots of shade from trees and buildings. This might be the time to try and run, if it is safe, before sunrise or after sundown. Check a weather channel for the constantly changing optimal running times. Unfortunately, these stretches may be a challenge to put into your 24-hour schedule.

Protection is crucial on sunny, cloudy, rainy, snowy, and foggy conditions.  The sunscreen on the skin is a basic protection along with garments that protect you from the sun’s UV rays. Do not forget the hat with the big brims or an ideal hat combination that covers the head, face, ears, nose, and neck. Wrap-around sunglasses will protect your eyes and also delay the onset of wrinkles around your thin-skin eyelids.

SPF clothing

If you are tempted to purchase clothing with a SPF (sun protection factor) don’t. There is no way to know what you are buying. If clothing is sun protective, it would be rated with a UPF (Ultraviolet Protection Factor) number. This rating is based on its thickness, tight weave, stretch, weight, finish, color, minerals and/or chemicals infused into the individual fibers or fabrics. The fabric should be tested and certified by an independent testing company to confirm its rating. It is important to adhere to the washing instructions.

For example, a famous branded running T-shirt fabric earns a numerical rating of 40 by an independent testing agency. This indicates that the fabric will enable 1/40th or 2.5% of UV radiation to penetrate the fabric and harm the skin. If the rating was 50 it means that 1/50th of the UV would penetrate the clothing and allow the rays to bombard the skin. The highest number a fabric can have is 50. This means that 2% will still constantly impact the skin. The highest rating that is allowed is 50+. This 50+ rating signifies that less than 2% radiation will reach the skin. The Australian and New Zealand Standard for the evaluation and classification of sun protective clothing, AS/NZ 4399 is considered the benchmark for the industry.

Sunscreen Background

Sunscreens are regulated by the FDA (Food and Drug Administration) in the United States.

How Much Sunscreen to Apply

A sunscreen product can be a lotion, spray, stick, or balm that contains one or more physical blockers (minerals), and/or chemical filters) as shown in Figure G. These manufactured goods protect exposed skin from UV B rays for a maximum amount of time based on the manufacturer’s instructions before it is necessary to reapply sunscreen to maintain safety. The protection measures will definitely be reduced if the bare skin comes in contact with clothing, sweat, rubbing, wiping, wind, and/or water.

Just like the clothing rating system, the SPF (sun protection factor) will never be 100% effective. The calculations are extremely complicated. The SPF rating system for sunscreens does not operate in a straight line. Higher numbers do not mean significantly more protection. The UPF for clothing is very easy to understand.

Any SPF rated product starts to provide diminished additional protection as the SPF rating that provides UV protection as the percentage of UV is reflected off the skin or is absorbed into the skin increases past 30. The rating of ultraviolet protection is only for UV B. In our country UV A is not rated at the present time. Could new government regulations that hopefully become available this year change this?

If the product contains two physical blockers, this mineral product is still only rated for UV B. The percentage of the mineral(s) will provide the level of protection provided. If a product provides UVA and UV B safety, it will indicate “Broad Spectrum” safety. Remember that products marketed in the United States DO NOT provide any specific SPF rating for UV A safety, only UV B security.

If the manufacturer’s rating indicates a plus after the SPF product rating number, it indicates that the UV B protection exceeds the posted value.

The Future

My forthcoming article will discuss the conflicting information provided by manufacturers, government, and common sense.  As of now only one non-profit organization, EWG (Environmental Working Group) and Market Watch (profit organization) both recommend a Blue Lizard® sunscreen for use. This information was accessed 9/8/19. Discussion of why only two ingredients are considered generally safe and effective will be in the next article.


Question: Do runners having dark skin need protection from the sun?

Question: Do you need to use a sunscreen during the winter?

Figure A
Figure B
Figure C
Figure D
Figure E
Figure F
Figure G

Categories: Features

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