The Sun, UV and Cancer

A history of UV in healthcare and its link to cancer

Joan Tanous
January 23, 2020
February 10, 2020

When thinking about the ideals of beauty for the western world, tanning and tanned skin is a popular component, however throughout much of history it was paler skin that indicated a higher social class: it signified that the person did not need to labour away in the sun all day to make ends meet. This perception changed around the time of the Industrial Revolution, when the working classes commonly earned their living down mines and in factories, and often lived in cramped and murky settlements. By contrast, the easing prices of commercial travel allowed the middle and upper classes to holiday on sunny coasts — and thus the glamour of a suntan was born. In the 1920s, Coco Chanel was photographed sporting a suntan in the French Riviera, and the story goes that this event sparked the desire for bronzed skin. But what is the science behind tanning, and what damage is it inflicting?

UV, or ultraviolet radiation, is a type of energy produced by the sun. There are three types of UV rays, each distinguished by their wavelengths:

  • UVB rays are the chief culprit behind sunburn. They have short wavelengths that reach the outer layer of your skin where they damage the DNA inside skin cells.
  • UVA rays have a longer wavelength and therefore can penetrate further, reaching the middle layer of your skin known as the dermis. These are responsible for photoageing however, contribute less to sunburn than their UVB counterpart.
  • The third type is UVC, which never reaches us as it is absorbed by the earth’s ozone layer. UVC rays can be artificially made, and are often used for their sanitising properties.

Your body’s response to UV damage is to distribute darker pigments to the surface of the skin (a tan) to protect the most vital parts of your cells.


Moderate UV exposure proves essential for good health. UVB exposure enables the skin to make vitamin D from cholesterol, and vitamin D is crucial to help the body absorb calcium and phosphate, which in turn leads to healthy bones, teeth and muscles. The World Health Organisation (WHO) states that 5 to 15 minutes of casual sun exposure of hands, face and arms two to three times a week during the summer is enough for essential vitamin D exposure. Too much UV radiation can damage the genetic material in your skin cells, which can cause skin cancer. Most skin cancers, in fact 9 out of 10 of the cases of melanoma in the UK are a result of too much sun exposure (CRUK). Certain cancers, such as basal cell and squamous cell cancers, have been typically found on areas of the body that are generally more exposed to the sun.

Phototherapy, a therapy that exposes the skin to UV rays for healing purposes, has been used as far back as the ancient Egyptians and Indians some 3,500 years ago. Toward the end of the 19th Century, Niels Finsen, a Danish-Faroese physician, was intrigued by the antibacterial effects of UV rays and designed the Finsen Light: an electric lamp that was proved successful in treating tuberculosis. Short-wavelength UVC light damages the DNA of tuberculosis bacteria and consequently kills them. In 1903, Niels won the Nobel Prize in medicine and physiology for his work on phototherapy. The usage of phototherapy was not only limited to the treatment of tuberculosis; it was also used to cure a wide variety of maladies in children, such as chest infections and anaemia.

Flash forward to the 1960s and 70s, and the link between the sun and skin cancer was becoming more publicly known, and the more widespread usage of antibiotics rendered phototherapy redundant for most purposes. It is still used, with effectiveness, to treat common skin conditions such as eczema and psoriasis: UV light has been shown to reduce inflammation for those suffering with psoriasis, and also slows down the production of cells. However, for the most part, UV therapy is not used much anymore for medical purposes.


Exposure to UV is a huge risk factor for the development of melanoma. Your risk of melanoma skin cancer is tripled if you get sunburned just once every two years compared to people who have never been sunburned (CRUK). Globally, skin cancer is one of the most common forms of cancer, and the numbers are on the rise. The British Skin Foundation says that the main preventable cause of skin cancer is UV exposure.

So, how do we ensure we stay safe in the sun?

  • Your first line of defence will always be the shade. Sunburn can occur in less than 15 minutes, so the best way is to limit your exposure, especially during the hottest parts of the day. CRUK recommends you stay in the shade between the hours of 11am and 3pm to avoid the UV rays at their strongest.
  • Your clothing will also have an impact on your UV exposure: the more, the better. A long-sleeved t-shirt will be more protective than a short-sleeved t-shirt, and sunglasses and hats are wise to wear in the sun as well.
  • Finally, a generous application of a sunscreen with at least SPF30 and a 4- or 5-star rating to cover up bits that aren’t protected. When using sunscreen, it is important that you ensure you apply enough (around 2 teaspoons for your head, arms and neck), and you reapply regularly (every 2 hours or so, depending on what you’re doing).

Tans may go in and out of fashion, but having a natural tan is never a positive thing: it’s your body trying to repair damage caused by the sun. Responsible sun exposure may be essential for a healthy lifestyle, but if you desire a bronzed look, you should instead opt for some self-tanning products such as creams and mousses. In an age of the beauty-obsessed, remember that healthy skin will always be ‘in’.


  • Written by Joan Tanous, Operations Associate at CCG.ai
  • Edited by Belle Taylor, Strategic Communications and Partnership Manager at CCG.ai, who also provided valuable thoughts on drafts of this post

References consulted:

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