You obviously like headaches
72 Hz is the minimum ergonomic refresh rate. Anything lower will give you headaches and will make you tired quicker. But OK, that's your problem.
Change the vertrefresh from 50.0 - 120.0
to 50.0 - 60.0
should do the trick. If the system insists on higher than 60 after the modification, please come back. As you're using an nvidia driver, there might be a setting in the device section that needs to be added.
PS Don't forget to restart the xserver after the modification.