How We Tan
Skin colour is dependent on a pigment called melanin. This is produced by specialized cells called melanocytes. Melanocytes produce packets of melanin called melanosomes and transfers them to the skin cells of the epidermis. Melanocytes are found throughout the skin. All races have the same number of melanoctyes. Black skin, however, has more melanosomes, giving better sun protection and more pigmentation.
There are two types of melanin pigmentation:
Genetically inherited skin tone
The other caused by sun exposure
Melanin protects your skin by absorbing harmful UV radiation and it darkens when doing so, producing pigmentation and leaving you with a sun tan.
Sunburn is a reaction to exposure of UV radiation. The superficial layers of the skin release chemicals that cause your blood vessels to expand and leak fluid causing swelling, pain and redness. Without sun protection, UV radiation penetrates deep into the layers of the skin causing damage to the skin cells. Skin turns red within 2-6 hours of being exposed and reaches peak redness after 8-24 hours. It can take several days for the redness to subside.
Danger times for sunburn
UV radiation is most intense between 11am to 3pm in the British summer time. In Australia, sunburn can occur in less than 15 minutes sunbathing on a clear summer's day. People are most likely to get burnt when participating in sports or leisure activities and are not thinking about the sun and protecting themselves.
Damaged skin cells self-destruct and peel off in sheets. It is the body’s way of ridding itself of damaged skin cells that might develop into cancers
Sunburn and skin cancer risk
Studies show that sunburn during childhood can double a person’s risk of skin cancer (1,2). Further studies looking at migration have found that individuals moving to areas with higher UV exposures eg. Australia have higher melanoma risks if they arrive as children than as adults (3,4.) Interestingly, protective attitudes to sun exposure during childhood can lead to fewer moles, a known risk factor for melanoma. Hence it is imperative that children are educated about sun protection and sensible precautions. Further work has shown that some people have a higher risk of melanoma if they have fair skin, blue, green or hazel eyes, freckles (5), and tan poorly or burn easily (6).
Awareness of these facts and protecting your skin when UV radiation levels are dangerous can avoid sunburn and lower your risk of developing skin cancer.
For information on how to adequately protect yourself, please see our page on protection.
1.Elwood, J. and J. Jopson, Melanoma and sun exposure: an overview of published studies. Int J Cancer, 1997. 73: p. 198-203.
2.Gandini, S., et al., Meta-analysis of risk factors for cutaneous melanoma: II. Sun exposure. Eur J Cancer, 2005. 41(1): p. 45-60.
3.Khlat, M., et al., Mortality from melanoma in migrants to Australia: variation by age at arrival and duration of stay. Am J Epidemiol, 1992. 135(10): p. 1103-13.
4.Mack, T. and B. Floderus, Malignant melanoma risk by nativity, place of residence at diagnosis, and age at migration. Cancer Causes Control, 1991. 2: p. 401-11.
5.Gandini, S., et al., Meta-analysis of risk factors for cutaneous melanoma: III. Family history, actinic damage and phenotypic factors. Eur J Cancer, 2005. 41(14): p. 2040-59.
6. Gallagher, R., et al., Sunlight exposure, pigmentation factors, and risk of nonmelanocytic skin cancer. II. Squamous cell carcinoma. Arch Dermatol, 1995. 131: p. 164-9
Read the facts about sunbeds