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Exercise heart rate can be determined by using the Karvonen formula**. Add the given percentage of
heart rate reserve to resting heart rate.
Exercise HR = % of target intensity (HR
max
– HR
rest
) + HR
rest
Example:
Target intensity 70 % HRR for a person with HR
max
201 bpm and HR
rest
50 bpm
Exercise HR= 70% (201-50) + 50
Exercise HR=156 bpm
For a precise exercise heart rate, you need your exact HR
max
and HR
rest
. When using estimated HR
max
,
exercise heart rate values are always estimates.
*In Polar RS800CX training computer, the heart rate value during a resting state is measured in a
sitting position (HR
sit
). This is for practical reasons since HR
sit
is used in energy expenditure
calculation because of accuracy. HR
sit
matches the low intensity to which different exercise intensities
can be compared.
**Karvonen M, Kentala K, Mustala O. The effects of training on heart rate: a longitudinal study. Ann
Med Exp Biol Fenn 1957; 35: 307-315.
Heart Rate Variability
Heart rate varies with every heartbeat. Heart rate variability (HRV) is the variation of beat to beat
intervals, also known as R-R intervals.
HRV indicates the fluctuations of heart rate around an average heart rate. An average heart rate of 60
beats per minute (bpm) does not mean that the interval between successive heartbeats would be
exactly 1.0 sec, instead they may fluctuate/vary from 0.5 sec up to 2.0 sec.
HRV is affected by aerobic fitness. HRV of a well-conditioned heart is generally large at rest. Other
factors that affect HRV are age, genetics, body position, time of day, and health status. During
exercise, HRV decreases as heart rate and exercise intensity increase. HRV also decreases during
periods of mental stress.
HRV is regulated by the autonomic nervous system. Parasympathetic activity decreases heart rate and
increases HRV, whereas sympathetic activity increases heart rate and decreases HRV.
HRV is used in the Ownzone, OwnIndex, and in OwnOptimizer features. It can also be monitored on its
own using the training computer. If your HRV changes at a given pace and heart rate, this may
indicate a change in your training load and stress.
Running Cadence and Stride Length
Cadence* is the number of times the foot with the stride sensor* hits the ground per minute.
Stride length* is the average length of one step. That is the distance between your right and left foot
Polar RS800CX User Manual 48