How many hours of audio recording will battery allow?

I'm thinking about getting the Apple Watch 3 for recording everything while I'm at work because someone falsely accused me of saying something unprofessional so I need to do something to protect myself from future false accusations. I'm assuming there is an app that will allow me to record continuously. I've heard the Apple Watch battery life is not great. If I were to disable unnecessary watch functions and only run an app that records audio how many hours could I record before the battery dies? Thanks!