Sipping Water to Stop Panic:  As a hypnotherapist  I work with people who have panic attacks.  I came up with a really easy to use plan to stop the panic cycle and it includes taking a sip of water and saying a few simple  words, it really does help to stop the panic.     
So the answer is a big yes, water is my go to drink for myself as well.  I really appreciated the list of things that lack of water can create - a  big reminder to drink water for many other reasons in addition to calming a panicking mind.