I trained for a 1/2 marathon once and I remember all the experienced runners doing 5 and 1's. Which is run 5 minutes and walk 1. But you have to work up to this. Start with 2/1's or 3/3's just to see what you can do without pain. and make sure you take it easy at first as you don't want to injure yourself. Running on sand is a super workout, but it can really mess your body up as there are not solid surfaces and your body has to adjust with each step. I know I tried it when I had a bit of knee pain and I haven't been back since...my knee was killing me so. But everyone is different!