运动对于防晒指数的影响

Sun protection factor persistence during daily physical exercises

目的:研究运动对防晒指数(SPF)的影响,以利于指导防晒霜的合理使用。方法:将24位志愿者的背部划分为4块区域,1块用于测试最小红斑量(MED),另3块以标准剂量涂抹防晒霜。实验环境温度为29～32℃,试验期间志愿者进行2次运动,并分别于0.5 h、4 h、8 h时进行中波紫外线(UVB)照射并测试即时最小红斑量(UVB-MED)。SPF的计算公式为UVB-MED/MED。结果:模拟夏季的运动环境下,防晒霜的SPF 8 h后衰减了73.9%,4 h后衰减了51.1%,运动后用毛巾轻拭汗液对SPF的衰减差异无统计学意义。结论:运动对防晒霜的SPF有一定影响。

Objective： To evaluate the sun protection factor persistence during daily physical exercises and to find out the effective way to use sunscreens. Methods： Four areas were marked on the back of 24 volunteers. One area was tested for minimal erythema dose （MED）. Three areas were applied with sunsereen cream （2 mg/cm2）, then the participants performed physical exercises. They were exposed to a hot environment and were photo-tested with ultraviolet-B （UVB） radiation for 30 rain, 4 and 8 hours after sunscreen cream application. The sun protection factor （SPF） was calculated, as MED on protected skin/MED on unprotected skin. Results： The sunscreen cream reduced by 51.1% after 4 hours and 73.9 % after 8 hours re- spectively. Conclusions： Daily exercises have a certain influence on sun protection factor of the sunsereeen cream.