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Tuesday, March 31, 2015
I would like to know when is the peak time when people need to avoid the sun inorder to avoid the long-term harmful effects of sun. Can you also let me know how long before do we need to apply the sunscreen before we go out inorder to get the full effect of the sunscreen. What is the best SPF number that we have to look when we buy a sunscreen. Can you suggest some sunscreens that is safe and effective?
It depends on where you live but in general the peak time to avoid being out in the sun is between 10 and 3. However, you can still get damage if you go out unprotected before or after these times.
You should apply sunscreen at least 15 minutes prior to going out in the sun, and you need to use at least a shot glass full of sunscreen every time you apply it. The SPF is an individual issue because all it means is that it gives you X amount of extra time out in the sun before you burn. So if you are very fair and will get a sunburn after 15 minutes out in the sun, then if you use an SPF of 10 you theoretically get 150 minutes. However, this time varies with the amount that you sweat, whether you are in the water, or whether you are playing a sport where the sunscreen could get rubbed off.
Reapplication every hour or so is a good idea, even for sunscreens that say they are water proof. It is very important that you use a sunscreen that protects against UVB AND UVA. Look for ones that contain Helioplex, or Anthelios SX.
Tatiana M Oberyszyn, PhD
Associate Professor of Pathology
Associate Professor of Molecular Virology, Immunology & Medical Genetics
College of Medicine
The Ohio State University