True Fitness Z7 Series - Manual (Page 56)

A
PPENDIX
A - T
ARGET
H
EART
R
ATE
C
HART
76
Because CHR is already trying to detect a fainter signal compared
to a chest strap, it takes less of a vertical heart position to cause it to
stop working. Depending on the CHR system, somewhere between
3% and 5% of the population cannot be picked up by any contact
heart rate monitoring system.
This heart-in-the-chest-cavity position is by far the leading cause of
CHR performance variation among individuals. Other factors which
negatively affect CHR performance are:
1. Dry or dirty hands.
2. Lotion or moisturizer on hands.
3. Excessive upper body motion, such as when using cross-trainer
ellipticals and in running.
4. Excessively tight grip.
5. Erratic or labored breathing or excessive talking.
C
AUSES
OF
CHR
P
ERFORMANCE
V
ARIATION
Z 7 Tr e a d m i l l O w n e r ' s G u i d e