Exposure to the sun can cause your skin to wrinkle and age prematurely, give you skin cancer and even interfere with your body's ability to fight off infections.
The sun's two ultraviolet rays -- UVA and UVB -- can be extremely damaging. UVB primarily causes sunburn and skin cancer, while UVA primarily causes premature aging and wrinkling. Both can cause aging and cancer, though.
The ultimate way to protect your skin, although it is an extreme measure, is to stay out of the sun altogether; or, wear clothing that limits your exposure. However, some clothing is porous and does let the sun in.
Unfortunately, no sunscreen can entirely block out the sun's damaging rays. To be on the safe side, use a broad-spectrum sunscreen, such as Photoplex, that works to block both UVA and UVB rays. Look for ingredients such as oxybenzone, dioxybenzone, Eusolax 6300 or 8020, Parsol 1789, lawsone with dihydroxyacetone, 2-ethylhexyl 2-cyano 3, 3-diphenylacrylate, sulisobenzone, red petrolatum or titanium dioxide. In the future, sunscreens will contain vitamin C to help control sun damage.
Most of us are familiar with the Sun Protective Factor (SPF) number on most sunscreens. SPF refers solely to protection against UVB rays. But if you apply a sunscreen daily, you needn't be concerned with the SPF value. All sunscreens can be washed off by sweat and swimming, so the most effective way to use a sunscreen is to apply it -- regardless of its SPF rating -- every day. This fixes the sunscreen's active ingredients to your skin so they cannot be washed off. And it's as effective with low-SPF sunscreens as it is with those that have a higher rating.
Q: How and why is ice used to relieve a sports injury?
A: When you are injured, blood vessels burst, filling the affected area with blood. Injured cells release large amounts of histamine-like compounds that cause fluid to accumulate. Applying ice will limit the swelling caused by the accumulating blood and fluid. The more you swell, the longer it takes for the tissue to heal.
But, leaving ice on for too long increases the swelling and delays healing. Never apply ice to an injury for more than 10 minutes at a time. The ice causes blood vessels to constrict and your skin temperature to drop. When your skin reaches 59 degrees, nerves cause blood vessels to widen; the skin will become hot, red and start to burn from an increased blood circulation. Called the "hunting phenomenon," this reaction occurs after 10 minutes of direct ice application.
When you are injured, stop exercising immediately. Elevate the injured part. For an extremity, wrap a compression bandage over the area and apply a cold pack or ice pack. Remove it after 10 minutes. You can apply the ice again for another 10 minutes, every 30 minutes, for up to the first 24 hours after the injury. If your skin begins to get hot and turn red, you've left the ice on too long.
Q: Does vitamin E prevent heart attacks?
A: According to research conducted at the University of Mississippi at Oxford, vitamin E helps to prevent plaques that block the flow of blood from forming in the arteries. These plaques can cause a heart attack.
The study showed that giving laboratory animals large doses of vitamin E prevented the buildup of plaques in arteries usually caused by eating a diet high in saturated fat.
We have known for years that saturated fat raises blood cholesterol levels and causes the formation of plaques in the arteries more than any other dietary component. Substituting unsaturated fat lowers cholesterol and helps prevent the formation of plaques. Interestingly, the same foods that contain large amounts of unsaturated fats also contain large amounts of vitamin E. Examples include vegetable oils, nuts and whole grains.
Researchers believe vitamin E helps prevent the formation of plaques that occur when large amounts of the bad LDL cholesterolaccumulate in the bloodstream. There, the LDL is converted to oxidized LDL cholesterol, which, in turn, forms plaques. Vitamin E is one of three anti-oxidant vitamins (the other two are vitamins A and C) which help prevent LDL cholesterol from being converted to oxidized LDL cholesterol.
There is no evidence that taking large doses of vitamin E by itself will prevent a heart attack. However, there is evidence that getting too little vitamin E in your diet can help cause one.
Thus, the most important way to avoid a heart attack is to stick to a low-fat diet that contains ample amounts of all three anti-oxidant vitamins. To make certain of that, be sure to eat fruits, vegetables, whole grains and beans.
Dr. Mirkin is a practicing physician in Silver Spring specializing in sports medicine and nutrition.