How does the sun affect the skin?
Sunlight is an essential source of energy and is vitally important to life. However, absorption of
incident solar energy by components of the skin causes premature skin aging, known as photoaging
(Berneburg, 2000; Hadshiew, 2000). Photoaged skin displays textural and pigmentary changes as
well as prominent alterations in the organization of connective tissue (breakdown of collagen and
elastin fibers) and cell death. The skin becomes wrinkled, less elastic, dry and rough, and uneven in
pigmentation.
What are the differences between UVA and UVB rays?
Most of the photobiological effects of the sun, including sunburn, sun tanning, and immunosuppression,
are attributed to UVB rays (290-320 nm). However, UVA rays (320-400 nm) can cause
more significant damage to the skin. Because they permeate more deeply into the dermal matrix
than UVB rays, UVA rays can induce long-lasting skin lesions and contribute to the formation of free
radicals (these are involved in the alteration of all skin compounds and in skin aging). UVA rays can
thus cause irreversible skin alterations and induce skin cancer (Mariéthoz, 1998).
What can you do to protect your skin?
The best protection against photoaging is avoidance of sunlight, particularly when it is at its strongest
(during the summer and in between 11 am and 3 pm). Remember to always wear sun protection, even
on winter days. Your sunscreen should block out both UVA and UVB rays and be SPF (Sun Protection
Factor) 30 or above. Clothes are also an effective means of protection against the sun
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