So you’ve heard how many runners and cyclists are using heart rate monitors to enhance their fitness and performance, but what is all the hype all about? Read on and we will take you through the ins and outs of heart rate monitor sports watches.
What is a heart rate monitor?
A heart rate monitor is a device that measures the beats of your heart in real-time. The standard heart rate monitor consists of a strap that wraps around your chest and transmits heart rate data to your wristwatch. Strapless heart rate monitors are available too, but are less common and lack the functionality of the chest strap design.
What are the benefits of using a heart rate monitor
A heart rate monitors lets you know how hard you are working.
Over training can be a problem for athletes when an individual’s exercise exceeds their capacity to recover. When this occurs, fitness gains cease and the athlete can begin to lose strength and fitness.
An elevated resting heart rate and a slower level of heart rate recovery are two symptoms that over training has occurred.
Comparing heart rates and recovery between training sessions over the same distance can be one of the most useful indicators of fitness level and a check for over training.
A heart rate monitor is a useful tool for becoming more intimately tuned into your body and knowing when it is time to adjust your training.
Features of a Heart Rate Monitor
Modern heart rate monitors share several features in common, yet there are also differences between them, here is a brief overview.
The Heart Rate Sensor
There are generally two types of heart rate sensor in sports watches:
Chest Strap Heart Rate Monitors measure normal exercise/activity and continuously monitor your heart rate.
Strapless Heart Rate Monitors work with ECG (electrocardiogram) accuracy to provide heart rate on demand (i.e. when you press a button). These types of monitors have sensors on the wrist, or are sometimes shaped like a glove with sensors on the finger area.
While the strapless models are more convenient and work well for measuring resting heart rate or light to moderate exercise, for more serious workouts the chest strap models are recommended.
The chest strap watches transmit a signal to a wrist watch unit. There are two transmission types: analogue or digital.
Analogue straps are the most common and provide accurate continuous heart rate data upload to a wrist watch. These units will also generally interface with most popular types of gym equipment, but have some deficiencies, with an analogue strap there is the potential for interference from other heart rate devices if you are in close proximity.
Digital straps transmit signal via Digital FM transmission, which is more robust and heavily reduces the risk of interference. On the down side, they do not interface with most gym equipment, but this is not usually a problem for most users.
In chest strap heart rate monitors, the ability to replace the battery battery is another point to consider as some of the leading manufacturers don’t permit it.
Target Heart Rate Zones or Training Zones
Most heart rate monitors will give you the option of measuring your heart rate against specified limits or heart rate bands. When using this feature, your goal then will be to keep your heart rate (measured in beats per minute) within a lower limit and an upper limit. This upper/lower range is called a Target Heart Rate Zone or Training Zone.
Many heart rate monitors - knowing that in different circumstances, different target heart rate zones apply - support multiple Zones, giving you the option of using one Target Zone for a gentle warm-up and another for the high intensity period of your workout.
Most heart rate monitors also offer a Zone Alarm feature, which alerts you if you are training out of your zone.
Real-Time Information
Heart rate monitor watches will display feedback on your heart rate while you are working out. Perhaps the most obvious display field is your Current Heart Rate, but there are usually several other options too.
Here are some of the more common ones:
| Current Heart Rate |
Your heart rate at a moment in time |
| Average Heart Rate |
Your average heart rate, taken over the current period of measurement |
| Maximum Heart Rate |
The maximum beats-per-minute your heart rate achieved for the current period of measurement |
| Minimum Heart Rate |
The minimum beats-per-minute your heart rate achieved for the current period of measurement |
| Calories |
The number of calories burned in the current period of measurement |
| % Information |
% of HR, % Avg HR, % Max HR, % Min HR, % Fat Calories Burned |
Recovery Information
Once you have completed a workout, your recovery heart rate information can be an important guide in determining if you have had enough rest before your next effort and as previously mentioned, a general indicator of over-training when compared to your recovery rate in similar sessions.
Some sports watch heart rate monitor support this feature, so it is worth looking for when making your decision about which watch to buy.
Post Session Information
When you have finished your session, most heart rate monitor watches provides you with stats and data for the session as a whole.
Some common analysis values are:
- Time Spent in Zones
- Average Heart Rate
- Minimum.Maximum Heart Rate
- Average Heart Rate For Each Lap
- Heart Rate Recovery
- Calories Burned
Calories Burnt Using a Heart Rate Monitor
Many heart rate monitor watches provide the measuring of calories burned in a session.
It’s important to be aware that sports watches are configured to only measure calories while performing exercise. If used during the day you will most likely get inflated readings.
Heart Rate Monitor manufacturers calculate calories in different ways too, some include your metabolic rate (calories burnt while you are inactive) whereas others don’t.
Swimming and Heart Rate Monitors
Unfortunately most heart rate monitors are not designed to be used in water due to the inability to transmit FM waves under water. It is possible (but highly unlikely) to get a reading only when your chest area and the transmitter are clear of the water.
Also note, while most sports watches claim to be waterproof. You should never press any watch button while under water. This let’s water into the watch case and electronics and water don’t mix too well.
Problems Getting A Reading
A Heart Rate Monitor works by detecting the electrical stimulation of your heart. In chest heart rate monitors this detection process works due to the “electrodes” in the chest strap. Generally the better the fit of the strap, the greater the chance of picking up your heart beat.
It is essential when picking up a strong clear heart beat to wet the electrodes with water. The electrodes are usually 10 cm either side of the center of the chest transmitter on the side that touches the skin. When you exercise you will sweat creating the moisture you need naturally, however if this moisture dries out before exercise you may experience erroneous readings.
Should wetting the strap not prove effective, the use of a electro conductive gel (ECG) is recommended when using a heart rate monitor with a chest strap.
Other reasons for the cause of erroneous readings include a flat battery in the strap, external electrical interference - some environments may be subject to high levels of electrical noise. High voltage power lines for example can sometimes cause this, crosstalk - interference from other heart rate monitors or a poor fitting chest strap.
