Heart rate monitor

suffolkb

Just puzzled about this. I have heart failure,so the doc has told me to stop running and walk when my heart reaches 135 bpm.I have set my cardiosport monitor to beep when I exceed this figure (or go below 120).
When I run through a wooded area,the hrm starts to beep and show my pulse to be around 40.Any idea why this should be - the signal surely only goes from my chest to my wrist,so why should the trees make any difference?

penrhyn

Maybe the trees are subconciously calming you down!
Seriously though is this any wooded area or a specific one, if its the latter maybe there is a powerful radio transmitter in the area which is blocking the signal.
I've had that happen with car central locking in the past.

suffolkb

It seems to be all wooded areas.Also goes haywire when I pass the electricity substation,but that seems more understandable.It`s not a problem - just something that puzzles me on my run.
Occasionally,it shows my heart rate as zero.Not yet it isn`t.