In the meantime, I did some research about getting the right HRM though:
Who Can Benefit from a Heart Rate Monitor?
"Casual joggers and walkers: Recreational exercisers can benefit from heart rate monitors in the same way as elite athletes do. By aiming for fat burning and aerobic target zones on your HRM, you can ensure that you get more out of your exercise time than you would get from a typical stroll around the block.