Do you always wear sunscreen on sunny days when your out on your bike? I read an article in Readers Digest saying that you should be out in the sun everyday for 15 to 20 minutes without sunscreen to get your vitamin D. It says that vitamin D can actually help reduce the risk of some cancer's as well as other health problems and you can't overdose on vitamin D from the sun, but the threat of sunburn continues. It said for best results, expose at least 50 percent of your body, wearing shorts and a T-shirt or a bathing suit, if possible.