One of those posts that mystify me. "Grounding" suggests conduction of electrical charges, which shouldn't be caused by any increase of charged particles in the atmosphere around ones immediate surroundings, due to the presence of all the low energy, non ionizing radiation that is ever more saturating our surroundings. For millennia, we have been unwittingly exposed to a background radiation which is natural, and caused by radioactive elements all about us. Plus we are also the recipients of much cosmic electromagnetic radiation, some as energetic as the ionizing cosmic rays from space, through damaging ultraviolet radiation from a component of sunlight, to the background microwave signature, to great fluxes of just wisps of elementary particles such as the gazillions of neutrinos that flood our bodies without interaction with our biology.Truth is watch out for such claims for products which have "claims" which are easy to expound upon, but very difficult to qualify or quantify on a scientific basis.
Cortisol is being looked at, much as melatonin was, as a target for sleep control therapy, 'cause its obvious that "sleeping pills" are just not the answer.