Various health reports indicate that sitting for too long working on the computer is not good for health. I need an app that can tell me to take a break, for example once every hour of continuous work.

It would be optimal if it can automatically detect how long it has been since my display was last unlocked or logged in and count from that time. When I take a break, I will lock the display and unlock it when I'm back.

Is there any such app for Ubuntu which help the user take regular breaks?