I COULD go into a highly technical, neuroscience explanation here
There are plenty of amazing resources out there doing this (see in particular Clinical Floatation Website)
So I will keep this more in “lay terms”….
SO – floating …. What is it?
When you lay in a tank of water saturated with Epsom salts which make you float
If you are worried about feeling claustrophobic – you can choose to have the lid open and light on
However, ideally an hour in darkness and silence gives your brain a rest and reset from the usual external stimuli it has to ordinarily process
… and allows the lesser known sense of interception
For me – floating is just that UNBELIEVABLE “reset” to my mind and body
See my piece on The Mighty about floating and Complex PTSD