Exercise with pacemaker

[Beffohol]

I was implanted with a pacemaker last May for trifacicular block (slow/stopping rhythm) pretty much a-symptomatic ....I also have an artirial flutter which does cause discomfort when I have an episode. I am trying to keep fit, lose weight and generally keep mobile. I have used a Fitbit charge 2 for over a year now and tbh it has been fantastic in getting me up and active. My concern is that when I go walking (most days) I try to do over 5miles. My walks are always on the flat and are at a steady pace yet my heart rate often goes up to 170.….or spikes at upwards of 160. Is this normal? Should I be concerned? My resting heart is a healthy 59-62. When it peaks, I am often surprised....I don't particularly feel poorly ...my GP advised me to exercise.

[Mollydex]

Everyone is different but I run and cycle with a pace maker. I have sick sinus and bouts of af.