Summer running: Beware the sun

Running in the Florida summer presents its own set of challenges.  Many runners decrease their mileage during this time of year, while others change their  routines to run in the cooler morning or evening hours.  Still others stop running altogether during the summer (not recommended).

Sun exposure is both healthy and dangerous for the skin.  Sun exposure is healthy because it stimulates the body to produce vitamin D.  It can be unhealthy because sun exposure can damage the skin, leading to wrinkles and, even worse, skin cancers.

Sun exposure stimulates the production of vitamin D, thus its nickname as the “sunshine vitamin”.  Vitamin D is also found in many foods.  It has several functions in the body, especially the regulation of bone mineralization.  A lack of vitamin D results and the condition of softening of the bones called osteomalacia.  The pediatric form of osteomalacia is called rickets.  Vitamin D has also been shown to be useful in reducing blood pressure and depression.  It stimulates immune system function and may protect against certain cancers.

In addition to vitamin D production, sun exposure activates a chemical called nitric oxide, large amounts of which are stored in the skin.  Nitric oxide dilates blood vessels, reducing blood pressure, which lowers the risk of heart disease and stroke.  It also increases blood flow to the muscles, increasing power and endurance.

Now the bad news.  The ultraviolet (UV) rays of the sun damage skin.  Up to 90% of age spots and wrinkles are due to sun exposure.  Worse, UV rays cause skin cancer.  Up to 20% of Americans will get some type of skin cancer in their lifetimes.  There are 3 main types of skin cancer: Basal cell carcinoma (BCC); squamous cell carcinoma(SCC); and malignant melanoma.  The BCC and SCC are known as non-melanotic cancers and are not as dangerous as the melanoma. In  the USA, there are 80,000 deaths annually from all skin cancers, with 49,000 from melanoma and 31,000 from non-melanotic cancers.

The BCC is the mildest form of skin cancer.  It usually appears as a raised, smooth, pearly bump on exposed skin.  It also has visible blood vessels, which often bleed.  BCCs rarely spread to other parts of the body (metastasize) and are rarely fatal.

The SCC is more dangerous than the BCC.  It can appear as thickened patches or hard nodules.  It can also bleed or ulcerated.  It metastasizes more frequently than BCCs.

Melanomas are the most dangerous skin cancers.  Globally, 232,000 are reported annually, of which 55,000 are fatal.  Melanomas often begin as moles that change size and shape.  Melanomas are highly metastatic to other organs and then become more difficult if not impossible to cure.

You should check your body for new or changing moles at least monthly.  Any suspicious lesion should be brought to the attention of your physician.  If you are at risk for skin cancers (fair skin, history of previous skin cancers, etc.), an annual skin cancer screening by a dermatologist may be in order

Fortunately, it is possible to enjoy the benefits of the sun while preventing the risks.  This is accomplished by applying sunscreens.  Today’s sunscreens are very effective in blocking UV radiation.  Use one with an SPF (sun protection factor) of at least 30, which will block 97% of UV rays.  Use one that is sweat and water resistant, and apply often to exposed areas.

Unfortunately, the majority of runners still do not understand the risk of sun exposure.  A Runners World survey of 1550 runners found a 36% never wore sunscreen, 36% rarely use it, 19% usually use it, and 9% always do.

The scalp and face can be protected by wearing a book wide brimmed hat. This is very important as skin cancers often affect these areas.  Hats also keep the sun out of the eyes.

UV rays can also penetrate clothing.  A system of UV protection provided by fabric has been developed called UPF (ultraviolet protection factor) rating.  For example, holding with a UPF of 50 allows only 1/50th of UV rays to penetrate.

Finally, consider the eyes.  UV exposure can lead to the development of cataracts.  Wear sunglasses of block 99-100% of UV rays.  This will also prevent BCCs that often form around the nose and eyelids.

In summary, the heat and humidity of summer should not prevent the enjoyment of running.  Remember to stay hydrated and to protect  your skin and eyes from UV rays.

Posted in Blog.