First of all, what is a zero gravity chair?
Well, they do not make you weightless, that is certain. It is mostly a marketing tactic. They are called zero gravity because they resemble the way astronauts sit when lifting off. Because of the stresses involved when taking off vetically in a rocket, NASA discovered that the stress can be distributed safely across an astronauts body when they are in a reclining position.
These types of recliners are called zero-gravity chairs because of the position they assume when activated, o