Am I damaging my body?

I live in the U.K I take a bath once a week with zero cold water. It's never painful or even uncomfortable during or after but am I damaging my body in any way?

What is zero cold water?

As in, I don't add a single drop of cold water. I only turn the hot tap on. Most of the time the hot water runs out so I get in and add more hot water like 20 minutes later.