When sunscreens were first invented in the 1940s, the only choice people had
was whether to select a lotion, cream or oil.
We know that people have
different sun protection needs based on lifestyle, and their skin's sensitivity
to the sun. That's why there are so many products to choose from today, for
example products with SPFs ranging from 2 to 70. For those who are active
outdoors, there are waterproof and sweatproof products.
With all of
these options, how should people go about selecting the right products? To
ensure proper selection, four factors must be considered:
Skin Type
SPF
UV Protection
Activity, Time in Sun and Skin Sensitivity
The SPF of a sunscreen indicates how many times longer a person can remain in
the sun before beginning to burn by using it than if he or she were unprotected.
For example, by using an SPF 15 sunscreen, a person who typically begins to
experience a burn after only 10 minutes of exposure could remain in the sun for
up to 150 minutes before a burn occurred.
What are the differences between UVA, UVB and UVC
rays? UVB rays, which are more intense during the summer, at high
altitudes and near the equator, are far more powerful and potentially damaging.
They mainly affect the outer layers of the skin. They are the main cause of
sunburn, skin aging and skin cancer. UVC rays are blocked by the ozone layer and
do not reach the Earth’s surface.
UVA rays are relatively constant throughout the year, and while not as
powerful as UVB rays, penetrate more deeply into the skin. UVA radiation
contributes to premature skin aging, sunburn and cancer. UVA radiation is
prevalent in the light systems used in sun tan salons; these may emit two to
five times more UVA than what is found in natural sunlight.
How do sunscreens work? Sunscreen ingredients absorb or
reflect ultraviolet radiation by forming a barrier on the skin surface. Energy,
in the form of sunlight, is converted into heat when it comes in contact with
the sunscreen, which is dissipated.
In addition to the type of skin, one must also consider other factors, such
as physical activity and time spent in the sun in order to choose the right
protection. Since sunrays are present all year long, even in the winter and on
cloudy days, doctors recommend using a sunscreen every day. It is therefore
strongly suggested to apply a sunscreen before going outdoors and to reapply
out after swimming or engaging in any strenuous activity, after sweating or
towelling.
The information provided herein is of a general nature and is in no way
intended to replace the knowledge, assistance or diagnosis of your
physician or healthcare provider. All decisions regarding your health are
your sole responsibility and that of your physician or healthcare
provider, as the case may be. For specific guidance regarding your
personal health, we strongly advise that you consult your physician or
healthcare provider. Schering-Plough Canada cannot be held responsible
for any interpretation or misinterpretation you may make of the
information provided herein.
