Sun: The Burning Facts
Protect Yourself From The Sun’s Damaging Rays
Sunshine is an important component of most outdoor activities and a great mood enhancer, but excessive exposure to it can lead to much damage. As your skin is the largest organ in the body, and functions as the first line of defence, protection from the sun’s damaging rays is important for anyone who wants to grow old gracefully. It is also an absolute must for anyone who wants to limit his or herself from the risk of developing skin cancer.
When do you need sun protection?
Doctors will tell you that sun protection is needed all the time and they’re right. Realistically however it’s important anytime you’re outdoors between the hours of 10:00am and 3:00pm, when the sun is at its highest.
People don’t realise that they can still be burnt even when the sun looks like not shining. Overcast days are some of the worst times for being in the sun unprotected. And because ultraviolet rays can reflect off certain surfaces, people need protection from the sun when snow covers the ground and also when in the water, when lying or playing on the sand and even when on a cement or grass surface.
Understanding UV rays
Ultraviolet rays are the different wavelengths of energy that are produced by the sun. Even though harmful, the sun’s energy is necessary to all human life. Fortunately, as life on earth has evolved so has the capacity to tolerate UV rays. The most important protection against the damaging ultraviolet rays is the ozone layer – a layer in the stratosphere that absorbs most of the various types of UV rays before they reach the earth’s surface.
Most of this radiation or energy from the sun is invisible to the naked eye. The fact that the radiation is mostly invisible is likely the reason why the sun can be so harmful. It’s hard to convince a person to protect against something that can’t be seen. Of the ultraviolet rays, the two that are responsible for skin damage are UVA and UVB rays. The sun also generates UVC rays, but fortunately these extremely damaging rays cannot penetrate the ozone layer and therefore pose no threat to humans.
The longer and more prevalent of the two, UVA rays are responsible for long-term skin damage because they absorb deep into the skin. Their strength remains uniform regardless of the time of day or time of year. UVB rays are shorter and are what cause skin to tan or sunburn. Our bodies need UVB rays to produce vitamin D, an important vitamin. Their strength varies based on time of day, time of year, altitude and also distance from the equator.
The UV Index provides a daily forecast of the expected risk of overexposure to the sun and is measured in a scale from 0 – 11 (low to extreme) and it’s used to determine the intensity of the sun’s radiation, particularly the likelihood that skin will or will not redden when exposed to the sun for various periods of time.
Of the ultraviolet rays, the two that are responsible for skin damage are UVA and UVB rays
The two rays
UVA rays (also known as the ageing rays) are responsible for long-term skin damage because they absorb deep into the skin.
UVB rays are shorter and are what causes skin to tan or sunburn. Our bodies need UVB rays to produce vitamin D, an important vitamin.
What is SPF?
Sun Protection Factor (SPF) displayed on the sunscreen label ranges from 2 to as high as 100 and refers to the product’s ability to screen or block out the sun’s harmful rays. This is a sunburn metre and often products inadvertently allow tanning with enough sun exposure.
Sun Protection Factor is calculated this way:
Take the time you would normally burn in the sun without protection. 20 minutes will normally produce redness on a light skinned individual.
Multiply the number by the SPF of your product. Example: with an SPF 15 x 20 minutes of sun time = 300. This is how many minutes you can stay in the sun without burning. 300 minutes divided by 1 hour of 60 minutes = 5 hours of sun protection without a sunburn.
Consumers need to be aware that SPF protection does not increase proportionally with an increased SPF number. While an SPF of 2 will absorb 50% of ultraviolet radiation, an SPF of 15 absorbs 93% and an SPF of 34 absorbs 97%.
Although the SPF ratings found on sunscreen packages apply mainly to UVB rays, many sunscreen manufacturers include ingredients that protect the skin from some UVA rays as well. UVA light has not been formally tested for the FDA to acquire a SPF rating but manufactures commonly include them in a broad sunscreen or sunblock. These “broad-spectrum” sunscreens are highly recommended.
Sunscreen and sunblock
Sunscreens can be classified into two major types: chemical and physical. Chemical sunscreens contain special ingredients that act as filters and reduce ultraviolet radiation penetration to the skin. These sunscreens often are colourless and maintain a thin visible film on the skin. These sunscreens usually contain UVB absorbing chemicals and more recently contain UVA absorbers as well.
Physical Sunscreens, most often referred to as sunblocks, are products containing ingredients such a titanium dioxide and zinc oxide which physically block ultraviolet radiation (UVR). Sunblocks provide broad protection against both UVB and UVA light.