A heart rate monitor is a device that measures your heart rate. It consists of a transmitter attached to the chest strap and a receiver in form of a watch. When the heart beats, an electrical signal is transmitted through the heart muscle in order for it to contract. The transmitter picks up this signal and sends it to the wrist receiver which displays the data.
Why Use a Heart Rate Monitor?
A heart rate monitor shows you how hard you are working and measures the intensity of your workout. Optimal intensity is when you are working hard enough to positively affect your health by burning fat and building muscle. It will help you to achieve optimised training in which you don’t overwork yourself or work out too easily. Once you figure out your limits you will have clearer targets, be more focused, and you will achieve better results more easily.
Identifying Your Training Target
What is your goal? Do you want to improve your aerobic fitness, lose weight, are you coming back from a long break or do you have specific race goals in mind?
Calculating Your Heart Rate Limits
The advanced monitors have the capacity to calculate most of this data for you. For those of you who don’t have these features, the following formulas will guide you.
- Resting heart rate
Do this by counting your pulse for one minute while still in bed. Your resting hr may vary each morning. For better measurement, count it over 3 mornings, then add the measurements and divide by three (number of days). Find your resting heart rate as soon as you wake up (preferably do the counting when woken up naturally not by alarm). (ie Sunday=65, Monday=69, Tuesday=67; 65+69+67=201/3=67
- Maximum heart rate
220 minus your age (e.g. 220-36=184)
- Heart rate reserve
Subtract your heart rate reserve from your maximum heart rate (based on the maximum heart rate example: 184-67=117)
- Lower limit of your threshold
Maximum heart rate multiplied by 60% (184×0.60=110.4)
Heart Rate Zones
There are four main heart rate zones:
- Recovery or energy efficient zone 60-70%
Training in this zone improves the ability of your heart to pump blood and improve the muscles’ ability to utilize oxygen. The body becomes more efficient at feeding the working muscles, and learns to metabolize fat as a source of fuel. You will burn fat, may lose weight, and you will be allowing your muscles to re-energize with glycogen.
- Aerobic or target heart rate zone 70-80%
Training in this zone will develop your cardiovascular system. Your ability to transport oxygenated blood to the muscle cells and carbon dioxide away from the cells will be developed. It is also effective for increasing overall muscle strength.
- Anaerobic zone 80-90%
Training in this zone will develop your lactic acid system. In this zone the amount of fat being utilized as the main source of energy is greatly reduced and glycogen stored in the muscle is predominantly used. One of the by-products of burning this glycogen is lactic acid. There is a point at which the body can no longer remove the lactic acid from the working muscles quickly enough. This is your anaerobic threshold. Training in this zone helps to increase the lactate threshold, which improves performance. Training in this zone is hard: your muscles are tired and your breathing is heavy.
- VO2Max or Red line zone 90-100%
Training in this zone will only be possible for short periods. It effectively trains your fast twitch muscle fibres and helps to develop speed. This zone is reserved for interval running and only the very fit are able to train effectively within this zone.
Types of Heart Rate Monitor
There are two main groups of heart rate monitor: fitness/cross training monitors and running monitors. In both categories you have a range from basic to very advanced models. But the main difference between these two groups are the running features (in the running monitors) i.e. splits, laps, interval or countdown timer.
A basic model will give you the average and the maximum heart rate and the time of the workout; it allows you to set one target zone for your workout. It can also be worn as an everyday watch as it shows the time and date. A good example is the Polar FT2.
The more advanced the monitor the more features you get, for example calorie counter, workout storage (memory), multiple training target zones, running watch features- laps, splits, interval timer – set how much time you want to spend in what zone). Some monitors have an integrated GPS receiver that measures your distance and calculates related data, for example the Garmin FR 610. The advanced models also let you upload your workout to your computer for detailed analysis of your workout. You will see whether you followed your program, under or overachieved, and you can build on this to improve.