We’ve all heard that it’s important to use some kind of sun protection. But what exactly does the sun do to our skin? Sunlight emits two kinds of ultraviolet radiation: short-wave UVB and long-wave UVA, which cause damage to cells, DNA and collagen. This leads to skin cancer and photo-aging (wrinkles, decreased elasticity and pigment spots) of the skin. Despite mainstream thinking, we actually get most of our sun exposure while driving, walking into the grocery store or taking the dog for a walk. The time we spend outdoors for pleasure, work or sport just adds to the exposure. Ultraviolet damage is cumulative, so every minute outside counts toward increasing your risk. This means we need to change the way we think about protecting ourselves from the sun.

More Details about UV Damage

UVA and UVB rays come from the sun, cross through the atmosphere and land on your skin, where the rays can behave in three different ways:

  • The top layers of the skin reflect the rays with no resulting damage
  • The pigment known as melanin absorbs them without damage; or
  • The UVA and UVB rays hit a target in your body causing harm:
    • DNA >> direct damage >> skin cancer
    • Oxygen >> Free radicals >> inflammation, sunburn and skin cancer
    • Collagen >> break down >> wrinkles, dark spots, and sagging
    • Sunburn >> furthers inflammation and increases free radicals
    • Immune cell >> Decreased immunity >>increased infections and skin cancer
    • Eyes >> Sunburn, Cataracts, Macular Degeneration, Blindness, and Melanoma

The body has many mechanisms to fight the constant barrage of ultraviolet rays that come from the sun. The top layer of the skin known as the epidermis has two functions. One is to reflect some of the radiation and the second is to absorb it with the pigment in the skin know as melanin. The more melanin in the skin, the more absorption. That is why people with dark pigment experience less burns and skin cancer. The body’s response to increased ultraviolet radiation damage is to thicken the epidermis and produce more pigmentation, better known as a tan. Note: although you get increased sun protection after you get a tan, the fact that you have a tan indicates that your cells have already been damaged from ultraviolet radiation.

If the skin is not able to reflect or absorb UV rays, they will find a target in the skin. When DNA is the target, the bonds in the DNA change, leading to mutations. The body produces enzymes that repair the DNA, but they are not perfect. This means that not all damage will be fixed. The more damage that occurs and can’t be fixed, the more DNA mutations occur, increasing the risk of skin cancer.

If the target is oxidized, unstable free radicals are created, causing further damage to cells. This activity can be compared to a pinball machine where the ball bounces off the different bumpers. As the ball hits each ‘bumper,’ it actually destroys it. This process is known as oxidative stress, which can damage or destroy the cell. If the UV radiation becomes excessive, more free radicals form and the body is not able to deal with it. Inflammation then occurs, which promotes more free radicals and damage. This is known as a sunburn. The way the body deals with free radicals is by using antioxidants such as Vitamin A, C and E or enzymes such as catalase, superoxide dismutase and peroxidases that are able to quench the free radicals.

Skin Cancer Foundation and World Health Organization (WHO) Stats
  • 5 million people are treated for skin cancer annually1,2
  • Annually there are more new cases of skin cancer than the combined incidence of cancers of the breast, prostate, lung and colon3
  • 1 in 5 Americans will develop skin cancer in the course of a lifetime4
  • Ultraviolet radiation (UVR) is a proven human carcinogen5
  • More people develop skin cancer because of tanning than develop lung cancer because of smoking6
  • 90% of nonmelanoma skin cancer and 86% of melanoma skin cancers are associated with the suns UV rays7,8
  • 1 person dies of melanoma every hour9
  • Melanoma is the most common cancer of young adults 25-29 years old and the 2nd most common form of cancer for young people 15-29 years old10
  • Having 5 or more sunburns increases melanoma risk by 80%11
  • More than 90% of visible skin aging is caused by the sun12
  • Daily sunscreen use by adults under age 55 can reduce skin aging13
  • Daily sunscreen use results in 24% less skin aging13
  • 12-15 million people become blind from cataracts annually, of which up to 20% may be caused or enhanced by sun exposure14
  • Sun exposure decreases immunity increasing risk of infectious diseases and skin cancer14
  2. S. Department of Health and Human Services. The Surgeon General’s Call to Action to Prevent Skin Cancer. Washington, DC: U.S. Dept of Health and Human Services, Office of the Surgeon General; 2014: page 1
  3. American Cancer Society. Cancer Facts & Figures 2014. http:[email protected]/documents/webcontent/acspc-042151.pdf. Accessed June 2, 2014.
  4. Robinson, JK. Sun exposure, sun protection, and vitamin D. JAMA 2005; 294:1541-43.
  5. National Toxicology Program. Report on Carcinogens, Twelfth Edition. U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program. 2011: 429-430. Accessed February 12, 2012.
  6. Wehner M, Chren M-M, Nameth D, et al. International prevalence of indoor tanning: a systematic review and meta-analysis. JAMA Dermatol 2014; 150(4):390-400.
  7. Koh HK, Geller AC, Miller DR, Grossbart TA, Lew RA. Prevention and early detection strategies for melanoma and skin cancer: Current status. Archives of Dermatology. 1996; 132: 436-442
  8. Parkin DM, Mesher D, P Sasieni. Cancers attributable to solar (ultraviolet) radiation exposure in the UK in 2010. Br J Cancer. 2011; 105:S66-S69.
  9. American Cancer Society. Cancer Facts & Figures 2014. http:[email protected]/documents/webcontent/acspc-042151.pdf. Accessed June 2, 2014.
  10. Bleyer A, O’Leary M, Barr R, Ries LAG (eds): Cancer epidemiology in older adolescents and young adults 15 to 29 years of age, including SEER incidence and survival: 1975-2000. Bethesda, MD: National Cancer Institute; 2006.
  11. Wu S, Han J, Laden F, Qureshi AA. Long-term ultraviolet flux, other potential risk factors, and skin cancer risk: a cohort study. Cancer Epidemiol Biomar Prev; 2014. 23(6); 1080-1089.
  12. Gilchrest BA. Skin and aging process. CRC Press. 1984; 124.
  13. Hughes MCB, Williams GM, Baker P, Green AC. Sunscreen and prevention of skin aging: a randomized trial. Ann Intern Med 2013 June; 158 (11):781-790.