I’ve just started a training plan after having a week off running (following a 100km ultra). I did the Monday’s recovery run this morning, in Zone 1. My average HR was 145 and max 175. I had to deliberately slow down several times – the run was more of a very slow jog and there was walking. Putting aside that wrist based HRMs are notoriously inaccurate, why would my HRs be so high when I am hardly exerting at all? I was also informed the my LTHR had increased … should I adjust my zones according to this advice, or not?