True Manufacturing Company Z5.4 - Manual (Page 15)

Z5.4 & Z5 Treadmill Owner’s Guide
15
A Note on CHR Accuracy
CHR monitoring may be a bit less accurate than a chest
strap, since the heart rate signals are much stronger at
the chest.
About 5% of the population cannot be picked up
by any CHR system. This is because their heart is
positioned in a more up-and-down manner in their
chest, as opposed to leaning over to one side.
Contact Heart Rate
Chapter One: Basic Operation