PT: "Don't look further, it's because you don't drink enough"

First meeting with PT: During the interview, even before the examination, I told her that I don't drink the supposedly recommended 1.5l of water per day. Her reaction:

"Don't look further, that´s the cause".

She did the examination after the interview, though, where she didn´t detect any excessive or lack of muscle pressure.

So the theory is that drinking less than 1.5l of water, your bladder constricts and constricts, becoming hyperreactive in the end.

I don't check exactly how much water I drink during the day, drinking only when I feel the need: more like 3 glasses per day, but 1 l when I do exercises, probably. I've done that for decades, without really thinking about it.

Any idea about this? Thanks.