Sun Exposure: Finding a Balance
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Sun Exposure: Finding a Balance

woman sun sunglasses Skin cancer is the most common type of cancer diagnosed in the United States. Since the main cause of skin cancer is ultraviolet (UV) rays from the sun, people are becoming more conscious of the harmful effects of sun exposure.

Since the 1980s, Americans have transitioned from slathering on baby oil and baking in the sun to covering themselves with high SPF (sun protection factor) sunscreens and avoiding midday sun. While there are still many sun worshipers out there, most people are now aware of the risks of sun exposure.

The National Cancer Institute recommends using sunscreen with an SPF of at least 15, not staying under the sun for long periods of time (especially from mid-morning to late afternoon), wearing protective clothing (eg, sun hats, long sleeves), and avoiding sunlamps and tanning booths.

The sun, however, does have certain health benefits. It can enhance your mood, protect against certain diseases, and boost your level of vitamin D. So should sun protection guidelines change? Should people work to balance their level of sun exposure—finding a common ground between getting enough, but not too much, rather than avoiding the sun altogether?

Sunlight and Skin Cancer

Melanoma is the most deadly form of skin cancer. While non-melanoma skin cancers (basal and squamous cell carcinomas) rarely spread, melanoma can spread to other parts of the body.

Ultraviolet rays from the sun are the main cause of skin cancer. Where you live may also be a risk factor. For instance, a study published in the Archives of Internal Medicine found that people who live in states with a higher level of UV rays from the sun had an increased risk of squamous cell carcinoma. States with a higher amount of UV rays included Connecticut, Indiana, Arizona, California, and North Carolina.

The Benefits of the Sun

Mental Health

The warmth and light generated by the sun can enhance your feeling of well-being. Sun exposure can also help prevent seasonal affective disorder (SAD), a condition that results in bouts of depression in the late fall and winter, when exposure to sunlight is reduced.

Vitamin D

Furthermore, the sun triggers your skin to synthesize vitamin D. While vitamin D is found in foods, including fortified milk and cereals, cod liver oil, and certain fish, many people don’t get enough of it from foods, so the sun provides most people with their vitamin D requirement. The catch is that sunscreen blocks the production of vitamin D.

With 10-15 minutes of sun exposure to the face, arms, hands, or back without sunscreen at least two times per week, most people can get an adequate level of vitamin D. However, people who live in northern or cloudy climates during certain times of the year may not be able to synthesize enough vitamin D from the sun.

Adequate levels of vitamin D prevent rickets in children and osteomalacia in adults (both are diseases that weaken bones). In addition, vitamin D may help maintain a healthy immune system, promote normal cell growth, and prevent osteoporosis.

Researchers don’t yet know for sure, but some propose that increased levels of vitamin D associated with sun exposure may also have anti-cancer effects. In laboratory studies, vitamin D has been shown to inhibit cancer cell growth and induce death of cancer cells.

To Sun or Not to Sun?

Until there is enough evidence to make solid recommendations, the best advice is to use your own good judgment and talk to your doctor. Weigh your own personal risks versus benefits of moderate sun exposure and decide on a safe amount of sun for you. While anyone can get skin cancer, people with fair skin, light-colored eyes, blonde or red hair, a tendency to burn or freckle, and a family or personal history of skin cancer are at higher risk. For most people, spending 10-15 minutes in the sun two or three times per week before applying sunscreen is a safe, healthful way to get an adequate amount of vitamin D.

Fortunately, for the most part, skin cancer can be prevented with safe and consistent sun protection. But since the damaging effects of the sun start early in life, it is important to begin practicing sun protection in childhood.

RESOURCES:

American Academy of Dermatology
http://www.aad.org/

Skin Cancer Home Page
National Cancer Institute
http://www.nci.nih.gov/cancertopics/types/skin

References:

Devesa SS, Grauman MA, Blot WJ, Pennello GA, Hoover RN, Fraumeni JF. Atlas of cancer mortality in the United States: 1950 to 1994. NIH Publication No. 99—4564, 1999.

Dietary supplement fact sheet: vitamin D. Office of Dietary Supplements website. Available at: http://ods.od.nih.gov/factsheets/vitamind.asp . Accessed July 4, 2005.

Facts and statistics about skin cancer. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/chooseyourcover/skin.htm . Accessed July 4, 2005.

National Cancer Institute. Common cancer types. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/commoncancers. Accessed November 19, 2009.

National Cancer Institute. What you need to know about cancer: an overview. Available at: http://www.cancer.gov/cancertopics/wyntk/overview/page4. Accessed November 19, 2009.

Seasonal affective disorder. National Alliance for the Mentally Ill website. Available at: http://www.nami.org/Content/ContentGroups/Helpline1/Seasonal_Affective_Disorder_(SAD).htm. Accessed July 4, 2005.

Squamous cell carcinoma (SCC). EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php. Updated November 9, 2009. Accessed November 19, 2009.

The known health effects of UV. World Health Organization website. Available at: http://www.who.int/uv/faq/uvhealtfac/en/ . Accessed July 4, 2005.

What is skin cancer? American Academy of Dermatology website. Available at: http://www.skincarephysicians.com/skincancernet/whatis.html . Accessed July 4, 2005.

What you need to know about skin cancer. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/wyntk/skin/page1. Accessed July 4, 2005.



Last reviewed November 2009 by Brian Randall, MD


Last updated Updated: 11/20/2009

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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