There’s not much science behind it yet . But some shoppers are convinced that this $49 Grounding Mat from Amazon is improving the quality of their sleep, as well as relaxing their muscles and improving circulation. One unusual side effect was reported, however — and it has to do with your dreams. The mat is made of highly conductive polyurethane carbon leatherette and, according to the brand, “connects to the Earth” through a grounding cord and wall outlet while you sleep. It also allegedly