Wall Street Dermatology

Protect your skin: Sunscreen 101

Daily use of sunscreen is crucial for the health and beauty of your skin. Sunlight contains ultraviolet radiation (UV-A, and UV-B) that induces skin cancer development and accelerates skin aging.

A commonly held misconception is that sunscreens should only be used during sunny days or during sunny outings. Sunscreens really should be used daily on all sun-exposed areas of the body. Because ultraviolet radiation is invisible to the naked eye, how “sunny” the day appears is not a reliable indicator of the incoming UV radiation exposure.  Hence, UV radiation can be present in high levels even on an overcast, rainy day.

When choosing a sunscreen, look for a high SPF (sun protection factor).  SPF of at least 30, which blocks out 97% of the UVB, is typically recommended for everyday usage.   A higher SPF may be recommended for outdoor activities.

Always look for “broad spectrum” on the SPF label as an indicator of protection against UV-A and UV-B, both of which contribute to skin aging and skin cancer.

So how much sunscreen should be applied on the body? Generally, a shotglass (approximately two tablespoons) amount of sunscreen is sufficient for the average person. Remember that sunscreen should be applied thirty minutes prior to sun exposure, then reapplied every two hours especially for outdoor activities.  For outdoor activities that involve water exposure, look for the “water resistant” label that indicates the duration, typically 40 or 80 minutes, of sun protection while exposed to water.

When applying sunscreen, ensure coverage to all sun exposed areas of the body. Areas of the skin that are frequently overlooked include top of ears, back of neck, and lips.  An SPF lip balm is an ideal vehicle for application of sunscreen to the lips.

So will appropriate sunscreen application allow you to be safely exposed under the sun for longer periods of time?  Remember that sunscreen only filters out a certain amount of sunlight and that increased duration of exposure may cancel out the beneficial effects of sunscreen usage.  Prevention of skin cancers and sun induced premature aging depends on a combination of proper sunscreen usage and prudent sun avoidance.