Measured whilst watching TV last night, sat on the floor with my back against the sofa (so body/legs in L shape) and I got 52 BPM which rose to 56 BPM when I walked up stairs.
Last time I did a 'proper' just woken up test it was 44BPM.
I'm 45 and I love it when a doctor or nurse take my pulse and then take it again because they think it's too low!
Having had a fair bit of surgery I once set off the 'low' setting after an op because the machine recorded my heart rate as 39 BPM!