Health Center

Other Protection Measures:

A 4 inch brimmed hat reduces sun exposure by 70% to your head, face and neck... A white, dry cotton shirt provides a SPF of 8. The SPF increases if the fabric is dyed or thick... Sunglasses that block at least 98% of UVA and UVB should be worn. UVB radiation is linked to the formation of cataracts. The darkness of the lenses does not correlate with the UV protection.

It isn't just sunburn...

Heat exhaustion and its more serious relative heat stroke are triggered by over exposure to heat and sun leading to salt deficiency and dehydration. If you experience excessive sweating, muscle cramps, nausea or dizziness you should seek a cooler place, get plenty of liquids and rest. Heat stroke occurs when the body's cooling mechanism fails. Symptoms include failure to sweat, hot/red skin, weakness, and confusion. Emergency medical care is needed. Both can be avoided by keeping yourself well hydrated in hot climates, acclimating before vigorous exercise, and seeking shade and rest if symptoms develop.

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All Sunshine is Not Created Equal:

  • Maximum exposure occurs between 10 AM and 4 PM.

  • Intensity of radiation is much greater in the summer.

  • UV radiation increases 4% per 1,000 feet of elevation.

  • Reflected radiation is just as damaging as direct. Water reflects up to 100% of radiation, snow reflects up to 85% and sand or concrete r

    eflects 25% of radiation.

There are two basic types of ultraviolet rays that reach the earth's surface from the sun — UVA and UVB.

UVB rays are responsible for sunburn and play the greatest role in causing skin cancer. They affect the outer layer of skin, are filtered by glass and the intensity varies depending on time of day and year.

UVA rays also contribute to the development of skin cancer, penetrate more deeply into the skin and play a greater role in premature aging changes, including wrinkles. They are also responsible for photosensitivity reactions such as those caused by some medications. UVA rays are not filtered by glass, make up a much greater proportion of sunlight and have more constant intensity. They can penetrate cloud cover, pollution and about 3 feet of water.

About Sunscreen

A sunscreen's effectiveness in protecting the skin is expressed as SPF (sun protection factor). It is the measure of the ability of the product to block UVB rays. If you use a sunscreen having a SPF of 5 then theoretically you can stay outside 5 times longer before getting a sunburn than you could without the sunscreen. A SPF 15 sunscreen blocks 92% of UVB rays while a SPF 30 blocks 96% of the rays.

It is estimated that most people only apply 20-50% of the amount used to determine the product's SPF, so you are probably much less protected than you think. If your sunscreen is SPF 15 you may really only be getting a photoprotective power of 3.

There is no measure of UVA protection, so you should look for products that contain avobenzone (Parsol 1789), benzophenones, titanium dioxide or zinc oxide. These chemicals have UVA blocking abilities. Considerable exposure to UVA can occur even in the shade. It is particularly important to block UVA if you are outdoors for long periods on a daily basis or are on a photosensitizing medication. Tanning salons use UVA rays.

If you wear sunscreen that only blocks the UVB rays you can actually increase your chance of developing skin cancer because by blocking the UVB rays you can prolong your sun exposure and accumulate more UVA exposure. Many studies show that the probability of sunburn/sun damage actually increases for those that use sunscreen because they overestimate the time and thoroughness of the protection.

To get the most from your sunscreen:

  • Apply sunscreen every day — not just when it is sunny.
  • Apply sunscreen ~30 minutes before going outdoors to dry skin.
  • Apply it in adequate amounts — a minimum of 1 ounce is needed for adequate total body coverage (about a handful).
  • Be aware that water-resistant sunscreens protect skin for ~40 minutes of water exposure, whereas water-proof protects for ~80 minutes.
  • Know that gels work well for oily or sweaty skin, lotions for dry skin, sprays for the total body and sticks for ears, lips and around eyes.
  • Apply sunscreen before insect repellent if both are needed. It will reduce the effectiveness of the sunscreen by about a third. Do not use combination products.