So your thoughts. I'm 46, so do all the math and for an aerobic work out it says that 80% is about 139bpm. Okay, I am still breathing through my nose at that point. Now if I go until I can talk (as some convential wisdom recommends) but not sing my HR is about 165-175, which is obviously way out of the 80% range. So what are your thoughts? My only bad is I am a type 2 diabetic. No sign of heart disease, no angina, no heart issues whatsoever.