The brain uses a lot of power to deal with the huge strain that gravity places on the body. In a floatation tank, your body is totally supported and you feel weightless. So because there is little for your brain to do, every muscle can fully relax.
With no commands needing to be sent out, activity in the logical side of the brain slows down until it synchronises with the creative side.
This will leave you in a dream-like state, similar to that experienced just before you go to sleep. In this state, the brain releases vast amounts of endorphins, a ‘feel good’ chemical.
While the state of relaxation may be deep and profound, your brain will stay dreamily alert. To get technical, the brain waves gradually shift from their usual alpha state to generate theta waves. This is the state of mind that Buddhist monks try to reach through hours of meditation and years of training. You can achieve this very quickly with the aid of floatation.