It is all about taking a bath.
Why would nature allow us to experience feet 1st to feel water?
Looks like there is a scientific reason on why our feet should feel the water first, it has something to adaptation of our body with temperature.
I have heard from my friend’s grand parent that this is the right approach.
Not sure about whether the professor had written this, but the information written above makes sense.
Hope you will make the change and share this piece of information and save lives.