Your MHR will change as you train... but very slowly, and only by a few beats. Maybe over years, it will get higher... but basically it naturally goes down and fitness increases it.. so they cancel each other out. More than likely, your MHR is the same every year.....
SO to answer your question... nope.. I keep training at the same BPM, but I keep getting faster.
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2008 Cannondale System Six
2016 Pivot Mach 5.5