Heart rate is one of those odd things since we are all individuals. I got mine up to 198 bpm when I was attempting to find out my Max heart rate so that I could gauge exercsie on that. So, as long as you're healthy, feel no chest pains and can continue your run/walk you should be okay.
There is the Karvonen formula for heart rate which is more accurate 'cos it takes resting heart rate into account so it is kind of customised to each individual. There is also the RPE (rate of perceived exertion) that you could use. Just Google the two terms and you will get plenty of sites on them.
Happy running