I got myself an earthing sheet for my bed last week. Too early to report any benefits. But here is an interesting article linking the benefits of sleeping grounded to recovery from adrenal fatigue...
For those who wonder what I'm on about, grounding is walking barefoot. This connects you to the to the electric field of the earth and it neutralizes free radicals, prevents inflammation and regulates cortisol production. Grounding bed sheets are made of conductive material which you lie on and this is plugged into the earth pin of the electrical wall socket. So whilst sleeping you get the benefits of walking around barefoot.