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Appendix A
APPENDIX A
Contact heart rate monitoring (perhaps more accurately called
hand-touch heart rate monitoring) uses the same principles as
chest strap monitoring: electrically conductive pads detect the faint
electrical signals produced by a beating heart and are converted to a
data signal which can then be displayed digitally as a numeric beats
per minute value.
The only difference is that a chest strap is right next to the heart, so
the signals are relatively strong. Contact heart rate (CHR) using the
fingers and palms receives an inherently much fainter signal. This
is the sole reason for the performance differences between the two
systems. This is also the reason why CHR systems must typically
use two pads per side for a total of four detection pads, while a chest
strap uses just one pad per side; the extra pads are required to help
detect the fainter signal.
The electrical signals detected by heart rate monitoring systems are
a side-effect of the electrical control signals the heart generates to
fire its muscles in the right sequence. The signals start in the top, or
upper-right part of the heart (known as the sinoatrial node), then
travel down to the bottom, or lower-left part of the heart (known as
the Purkinje fibers). It is the fact that the heart is tilted in the chest
cavity, and thus these signals move from the right to the left side of
the body, that makes it possible for monitoring pads on each side of
the body to detect the heart rate. (The CHR pads correspond rough-
ly t
o leads I and III in a standard 12-lead ECG setup.)
If a person’s heart is tilted less than average, the signal is weaker.
(Note that this is not indicative of heart strength or health.) In some
people, their heart is nearly vertical in their chest, and even a chest
strap cannot pick up their heart rate signal. (12-pad medical ECG
systems still work well on such an individual.) Less than 1% of the
population are in this category.
Remember to check with your physician before beginning any
exercise program. She can help determine an appropriate target
heart rate. Medications often affect heart rate.
Robert Robergs, editor of the prestigious Journal of Exercise
Physiology, conducted a study in 2002 of the maximal heart rate
equation 220 - age. He found this equation “has no scientific merit
for use in exercise physiology and related fields.”
In his survey of research in this area, Robergs found several other
simple equations that were significantly more accurate. The best
equation he found was derived in 1994 by Oten Inbar:
205.8 - (0.685 * age)
The TS1 uses the Inbar equation. Even though this is the best
available equation, it still has a possible range of error of +/- 6 beats
per minute.
Other similar equations that are also more accurate than 220 - age
are:
206.3 - (0.711 * age) (Londeree, 1982)
206.0 - (0.700 * age) (Tanaka, 2001)
208.8 - (0.734 * age) (Robergs meta study, 2002)
Roberg’s paper can be found here: <http://www.asep.org/
Documents/Robergs2.pdf>
Check
With Your
Physician
A New
HRmax
Equation
88
T S 1 O W N E R ’ S G U I D E
Appendix A
APPENDIX A
CONTACT
H
EART RATE
M
ONITORING
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