A Guide to Heart Rate Monitors
How does a heart rate monitor
work?
It is essential when exercising that you workout
at the right pace and intensity. If you don’t push yourself
hard enough you will make little or no progress, and push yourself
too hard and you could risk an injury. Your heart rate is the
best indicator of your fitness level, and so essential to determining
which level you should exercise at.
The most accurate reading of your heart rate is
given from an electrocardiogram monitor. This monitor measures
the tiny electrical currents emitted by your heart’s movements
to give a reading of how times your heart beats in a minute. The
result is known as your electrocardiogram (ECG). However this
is a rather large machine and just a little awkward to exercise
with!
A heart rate monitor is a much smaller and more
convenient version of an electrocardiogram monitor, and does essentially
the same thing - measure your heart rate.
Which heart rate
monitor is best for me?
There are literally hundreds of heart rate monitors
on the market today, each with different features and programs.
This can make the process of choosing a heart rate monitor both
confusing and expensive. Therefore it is essential that you identify
only the features you really need.
So lets breakdown the options:
1. Straps or Strapless
The first thing to decide is whether you want
a heart monitor with or without a strap.
A heart rate monitor with a strap consists of
a belt transmitter that is worn around the chest and a wrist unit.
The chest belt measures the electrical signals from your heart
and transmits the results to the wrist unit. As contact with the
skin is continuous, your heart rate results will be displayed
continuously, and can guide you through your whole workout.
However a common problem with the chest strap
monitors is that the accuracy of the results can be distorted,
when results are transmitted between the chest and wrist units.
This is caused by interference from electrical waves emitted by
other sources like gym equipment and power lines. Other heart
rate monitors in close proximity can also cause interference.
This can be a real problem if you are using your heart rate monitor
at the gym or in a race.
So when choosing a heart rate monitor it is important
to check what type of transmission technology the monitor has;
analogue, coded analogue or digital.
The following table defines the different types
of transmitters:
| Analogue
Transmitter |
Coded
Analogue Transmitter |
Digital
Transmitter |
| Relays the least effective results as transmission
is subject to all forms of interference; other heart monitors,
gym equipment and power lines. |
Cuts out interference from other heart rate
monitors but is still affected by waves from gym equipment
and power lines. |
Greatest resistance to all forms of interference.
There are some highly tuned models that actually provide ECG
accurate results. |
So you can see the heart rate readings from analogue
and coded analogue transmitters can sometimes be unreliable.
It is also important to remember that regardless
of the transmitter, the accuracy of the results can still be affected
if contact between the chest belt and skin is not maintained properly.
This can especially be a problem for women, as the design of chest
belts is more suitable for men. As a solution there are now widely
available sports bras, which have been specifically designed to
hold the chest transmitter comfortably in place.
However if you do find chest transmitter belts
and bras too uncomfortable you may prefer a strapless heart rate
monitor.
A strapless heart rate monitor consists only of
a wrist unit. To get your heart rate reading you must place two
fingers on the wrist sensors on the unit. The results will be
quickly displayed on the heart rate monitor. As the reading and
result display is within the same unit there is also no possibility
of external interference affecting the results.
The disadvantage of these strapless models is
that the heart rate reading cannot be displayed continuously.
This in itself can be a problem, but it also limits the other
type of programs that can be made available on the heart rate
monitor.
| |
Advantages |
Disadvantages |
| Chest Belt Heart Rate Monitor |
Continuous heart rate readings. |
Interference can distort
the accuracy of results. |
| Strapless Heart Rate Monitor |
More comfortable. |
Heart rate reading is only
displayed when wrist sensors are activated. |
2.Wrist Unit Features
Both types of heart rate monitors have a wrist
unit and there are just a few simple things to be aware of. The
main thing to look out for is an easy-to-read display, big buttons
and easy access to the functions, which is particularly important
when you are exercising. Some watches also come with backlighting
and a zoom, which enlarges display.
Most heart rate monitors are also combined with
a digital watch and offer standard features such as, the time,
wake alarm, calendar and stopwatch.
3. Target Zone Alarm
We have already discussed the importance of exercising
at the right intensity. The most efficient level for you to exercise
at is known as your target heart rate zone.
Most heart rate monitors offer a target zone alarm.
You can use a chart to determine your target zone and enter this
into the heart rate monitor manually. Or you can choose a heart
rate monitor that has an inbuilt calculator, which will automatically
set your target zone when you enter in your age.
More sophisticated models can even determine your
target zone for each day based on your performance in a short
warm up. So if for example you have not fully recovered from the
previous day a lower target zone will be set to prevent you over
working your body. Likewise as your overall fitness improves the
monitor will set a higher target zone.
Once your target zone is set, if your heart rate
falls outside the upper or lower limit a light or sound alarm
will indicate that you are outside the zone. This ensures you
are always exercising optimally.
4. Exercise files.
In addition to these standard features, many models
provide a range of other data for each workout session such as:
- Date and start time of your exercise session.
- Total exercise time.
- Your average, minimum and maximum heart rate.
- Time in, below and above your target zone.
- Number of intervals.
- Your average, minimum and maximum interval heart rate.
For athletes there are some extra data options
to be aware of:
- A lap time indictor
- A lap number indicator
- Your average, minimum and maximum lap heart rates
The data will be available throughout your workout
as well as being recorded on to an exercise file. The exercise
file will recall the information at the end of the session like
a summary. This is a valuable tool in tracking your progress.
For example, if you have a planned program you
can compare how well you were able to follow it; identify which
areas of your workout need more attention and compare how different
aspects of your workout are affected in different activities.
However, it is important to remember that the
number of files that can be stored on your heart rate monitor
depends on the memory available. Some heart rate monitors offer
a very basic memory and recording function that will only recall
data on you last workout. Others can record new workout information
without deleting earlier workout data. In fact some of the latest
models have memory capacities that can store hours of workout
data and numerous exercise files.
5. Extra Heart Rate
Monitor Options
Most heart rate monitors offer additional features
that can help you improve the quality of your workout and chart
your progress more effectively.
So let’s consider the advantages of these
extra features and how useful they might be to you.
Calorie Calculator
By measuring your heart rate it is possible to
determine how much energy has been used and how many calories
burnt.
This feature can be a useful tool for someone
following a weight loss program that includes a calorie-controlled
diet. There are also more sophisticated models available on the
market, which display the total fat burn as well.
Even if you are not on a weight loss program this
information can be important. Knowledge on calorie consumption
is essential to refuelling your body correctly and optimising
your workout. This is particularly important in endurance activities
like distance running.
Vo2 Max Display
Vo2 is basically a measurement of how much oxygen
your body consumes and how well it is processed. Vo2 is most accurately
measured when you are exercising at your maximum heart rate. A
high Vo2 Max indicates you are fit and able to train intensely.
An increasing Vo2 Max is an excellent indicator that you are becoming
fitter and healthier, and is extremely motivating.
Altimeter
Many heart rate monitors include the functions
of an altimeter such as weather and temperature indicators. Another
popular feature is a chronometer that tracks your altitude.
These tools can be invaluable if you are involved
in outdoor activities, such as running, hiking, skiing and cycling.
With this information you can proactively adapt to the external
conditions, by adjusting your pace and intensity to optimise your
performance.
6. Speed and Distance
Sensors
There are host of additional inbuilt, arm and
belt sensors designed for analysing other aspects of a sport or
activity.
Odometer sensors measure the distance travelled,
and speed sensors measure the speed of that object be it foot,
ski, bike or boat. A new innovation is this area is the use of
globally positioned satellites (GPS). This new technology tracks
the speed and distance sensors using a network of global satellites
for increased accuracy.
There are more technical sensors available for
pedalling sports. These include cadence sensors that measure the
speed at which the cycle pedals turn. Other sensors available
measure how much power you exert on each pedal push, and even
the balance between left and right pedal pushes. These sensors
are likely to be most useful for the serious athlete only.
The information provided from these sensors can
be useful for pacing yourself, especially where you are following
a program plan or a race strategy. However the information will
be most useful in the post training sessions when the data can
be used to evaluate your total performance.
The following table summarises which type of sensor
would be most useful according to activity:
| Activity |
Odometer |
Speed |
Altimeter |
Power |
| Fitness |
X |
|
|
|
| Running |
X |
X |
X |
|
| Cycling |
X |
X |
X |
X |
| Rowing |
X |
X |
|
|
| Skiing |
X |
X |
X |
|
| Hiking |
X |
X |
X |
|
Data Analysis
Its great to have all this data, but it can be
confusing to understand how they all relate to the bigger picture.
We have discussed the use of exercise files. However, some heart
rate monitors only enable you to store data from a single session,
so you cannot track your long-term progress. But of course there
are other options available so that you can!
You will find there is software available for your computer that
not only analyses your heart rate monitor data, but can also help
you set goals, plan training sessions and chart you progress.
The first thing is to make sure of is that any
software you purchase is compatible with your computer and your
heart rate monitor.
The second thing to consider is which of the different
data transfer options you need:
- Manual: You will need to enter information
directly into the spreadsheet.
- Infrared Interface or Sonic Link technology:
The data will be transferred to your computer either through
a small recorder or directly from your heart rate monitor.
The software then creates a profile and a summary
of all the information that is much easier to understand than
just raw statistics. This profile is also a permanent record of
your fitness progress, which you can use for evaluation over time.
Heart rate monitor technology is developing day
by day; there are now options that enable you to get feedback
on your workout online and even through your mobile!
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