There can be several reasons for abnormal or irregular
readings during exercise. Due to the same reasons, heart rate may stay at
the same value for a long time or the heart rate stays at zero (0).
1. Poor contact between the skin and the
electrodes of the transmitter
For accurate heart rate measurement, the contact
between skin and the electrodes should be as good as possible. Polar
transmitters measure the ECG signal from the chest, where it is the
strongest. The weak heart-generated signals need to be accurately measured
before the calculation of the heart rate. It is therefore important to
ensure that the contact between the skin and the electrodes is as good as
possible. Here are some tips how to ensure good contact:
1.1. Moisten the grooved electrode areas on the back
of the transmitter. At the beginning of the exercise session your skin may
be dry and the moisture will help ensure better contact. When you start to
sweat the contact will improve because the salt in the sweat conducts the
electrical signals very well. Saliva is a good conductor as well.1.2.
Tighten the elastic strap of the transmitter. If the transmitter is loose,
the movement of the electrodes disturbs the detection of the ECG signal. If
the standard strap does not fit satisfactorily, larger and smaller elastic
straps are available as accessories.
1.3. The type of the ECG signal slightly varies from
person to person. The form of the ECG signal can depend on form of the
chest, the anatomical location and position of the heart, position of the
electrodes and the amount of body fat. If the ECG signal is weak,
disturbances can more easily spoil the signal. Find the best contact by
turning the transmitter left or right, or place it lower or higher. There
have been cases where the transmitter detects the heart rate better when it
is turned upside down so that the Polar logo is upside down and facing out,
or even when attached on the persons back with the Polar logo upside down
and facing out.
1.4. For active sports like aerobics or marathons,
women can use the accessory Heart Bra which makes the transmitter stay in
place better. Ask your local Polar dealer or distributor for the
availability of this product.
1.5. Hairy chest may also weaken the contact. Try to
find the best possible position for transmitter.
1.6. In demanding cases, use conductive electrode
lotion or gel to improve the contact. After using them, it is very important
to wash the transmitter carefully.
2. Wear and tear of the transmitter
Proper care of the transmitter after use ensures
longer service life for the transmitter.
2.1. Wash the transmitter regularly after use with a
mild soap and water solution. Dry it carefully with a soft towel after
washing.
Never store the transmitter when it is wet. Sweat and
moisture can keep the electrodes wet and the transmitter activated, which
shortens the battery life.2.2. Store your Polar heart rate monitor in a cool
and dry place. Make sure that the electrodes do not contact anything damp,
such as sport towel or wet elastic strap. Do not store a wet transmitter in
any kind of non-breathing material, such as a plastic bag or a sports bag.
2.3. Do not bend or stretch the transmitter. This may
damage the electrodes.
2.4. Only dry the transmitter with a towel.
Hard-handed handling may damage the electrodes.
2.5. Keep your Polar heart rate monitor out of extreme
cold and heat. The operating temperature is -10 ºC to 50 ºC/ 14 ºF to 122
ºF. Do not expose the Polar heart rate monitor to direct sunlight for
extended periods, such as leaving it in a car.
2.6. The transmitter can be washed with mild soap and
a gentle brush. If the electrodes appear discoloured, the transmitter needs
to be washed. Do not use any alcohol or a solvent based detergent.
3. Electromagnetic disturbances
Electromagnetic disturbances may occur near high
voltage power lines, traffic lights, the overhead lines of electric
railways, electric bus lines or tram lines, televisions, car motors, bike
computers, some motor driven exercise equipment, cellular phones or when you
walk through electric security gates. Check your surroundings and move away
from the source of interference, or remove the source of the disturbance.
4. The distance between the transmitter and
the receiver is too great
The maximum transmission range between the transmitter
and the receiver is 1 metre (3 ft). If the distance is greater, the receiver
may not get all the signals sent from the transmitter. In cases where the
transmission range is at it is extremes, for example rowing or biking where
the receiver is not attached to the wrist, the receiver may display the same
heart rate for a long time. To avoid this, keep the distance within 1 metre.
5. Signals from more than one Polar
Transmitter within 1 metre transmission range
Note only with non-coded transmitter (T31)!
In cases where are more than one transmitter nearer
than 1 meter, and you are using the non-coded transmitter, your receiver can
pick up the signal from all transmitters within the range, this can result
abnormal high readings. Even if the other transmitter is coded, and yours is
non-coded, your receiver may still give an inaccurate reading. To avoid
signal crosstalk, keep the distance to the other transmitters.
The coded transmitter and receiver system does not
pick up the signal from other heart rate monitors. In case of false readings
with a coded transmitter and receiver, check if the code has been locked.
After a successful code search, a frame will appear around the heart symbol
on the display. If the frames around the heart cannot be seen start the
measurement again and check that you are not near other heart rate monitor
users, because they may interfere the code search. Also, high voltage power
lines, televisions, mobile phones and other sources of electromagnetic
disturbance may interfere with the code search, as well as keeping the
receiver too close to the transmitter.
6. Static electricity, technical sportswear
and special conditions
If the humidity of the air is low, or you are
exercising in windy conditions (for example high-speed road racing), a
fluttering shirt may rub the transmitter and generate static electricity.
This causes additional signals, especially if the contact between skin and
transmitter is poor. To avoid this:
6.1. Moisten the electrodes before use, or use the
conductive lotion or gel
6.2. Use a cotton shirt instead of a synthetic shirt
6.3. Use a tighter shirt to avoid fluttering of the
material
6.4. Use the transmitter on a wet shirt
6.5. Wet the shirt
7. Arrhythmia
Polar Heart Rate Monitors are not designed to detect
arrhythmia or irregular rhythms and will interpret them as noise or
interference. The computer in the wrist receiver will make error
corrections, so that arrhythmia beats are not included in the averaged beats
per minute. The blinking heart symbol in the face of the wrist receiver,
however, will continue to show all heart beats received. In most cases the
Polar Heart Rate Monitors will work fine for persons with arrhythmia.
8. Battery of the transmitter is getting empty
The estimated average battery life of the Polar
Transmitter is 2500 hours of use. If the battery of the transmitter is
running low, the transmission range decreases and may cause errors similar
to the ones listed above in this document.
