Virtually all heart monitor systems come with a unit that you wear on your wrist, but there are two main ways that your heart is actually monitored. The first way is that the wrist unit actually has an electrode sensor on it; when you want to check your heart rate, you simply place your finger on the wrist unit sensor and it will read and display your current heart rate. The second way is that the heart monitor system has a strap that is placed around your chest; this strap has an electrode sensor built-in and reads your heart rate. The chest strap also has a transmitter that then sends this information to the wrist unit and displays your current heart rate.

Once you have a sense for which main type of heart monitor you're most interested in, it's time to consider some of the other features and functions:

Programming Features
Many heart monitors are really mini-computers and can keep track of a variety of measurements for you, including heart rate, percentage of maximum heart rate, training time, calories burned, percentage of fat burned, adjustable upper and lower pulse limit with optional alarm function, lap settings, pacer settings, interval training, high and low heart rate measurements, and more. Most heart monitors also perform basic watch functions: displaying time, date and weekday; programmable alarms; stopwatch; countdown; time zone adjustments, and so on.

In addition to taking and displaying these measurements, some heart monitors save the measurements as historical data that can be viewed, tracked and analyzed on an ongoing basis. This data can be saved in a variety of ways- an exercise diary, lap recall, heart rate memory recall (e.g., saves last 25 measurements), and so on. For those serious about tracking and analyzing performance, some heart monitors offer the ability to upload your training information to a computer for analysis. Special software is installed on the computer, and the connection between the computer and the heart monitor is either via a USB port or via infrared ports on the heart monitor and computer. The software program can then analyze and track your performance; you can even download settings from the computer to the heart monitor.

Transmitters
Transmitters are an important component of a heart monitor system, and it's important to consider the features of the transmitter just as much as you would consider the features of the wrist unit. Since the heart monitor-transmitter will be worn on a strap over your chest next to your skin, it's important that it's made of a washable, soft, fabric material (there are transmitter bras that are made for ladies as well). In many chest straps, the electrodes, which pick up the heart signals, are integrated right into the strap for added flexibility and comfort. Others use a small plastic transmitter attached to the strap. Chest straps and bras come in different sizes, so make sure to find one that will adjust to fit you comfortably.

The last point regarding transmitters is that many come with coded signals so that as the signal is transmitted from the electrodes to the wrist unit, it is not confused with any other heart monitor that might be nearby. This is of particular concern if you train with other people, or will train in areas (or race) near other people that might be wearing a heart monitor as well.

Ergonomics
In addition to the programming features and the transmitter, you should consider the ergonomics of the wrist unit, including the material it's made from (titanium, plastic, aluminum, etc.), the size and weight, the display options, any backlighting, buttons and ease of operation, low battery indicator, and so on.

Durability
Durability is of any heart monitor is hard to predict from reading a web site, but it's possible to get an indication based on the approved activities, whether the heart monitor is waterproof or water resistant, and what the warranty and battery life are. A good rule of thumb is that you should get at least 2000 hours of continuous use from the heart monitor, and the warranty should be at least one year on the wrist unit and 2 years on the transmitter.

Specialty Accessories
There are separate devices that can be used in conjunction with heart monitors to add to their training value. There are units and mounts made just for biking; they measure cycling speed and distance, pedal power and overall efficiency. There are also units for runners that utilize a foot accelerometer that translates inertial forces into running speed and distance.

How to find the best heart monitor for you
Naturally, the choice of the best heart monitor for you will be based on your particular situation, budget, and needs. Shopping for a heart monitor online is a great way to research and compare several types, models and brands of heart monitors to make sure you find what that will work for you based on your desired features. Online shopping can also be a lot more convenient and efficient than driving across and around town in person to various sporting goods stores. Once you know what specific features and functions you want from your heart monitor, you will just need to find some or all of the heart monitors that match your needs and begin comparing them by other factors:

Price- of course, price should be a consideration for any purchase you make, including heart monitors. All other things being equal, it usually makes sense to go with the service that offers the lowest price. However, don't make price your only criteria for choosing the best heart monitor.

Selection- finding just the right heart monitor for your needs is important, and there can be a significant difference in selection among heart monitor sites. Don't just stop on the first site and pick something- do a little bit of browsing among sites first. Some sites only sell their particular brand of heart monitor, while others sell heart monitors from the top manufacturers.

Customer service- the better the online heart monitor store, the better the customer service they will provide. Look for sites that have extensive FAQ sections, have a friendly interface, and several options to contact customer service (via email, chat, or by phone, etc.). Find out the hours customer service is open and how long the response time is.

Shipping- shipping costs add to the total cost of anything you buy online, including heart monitors and accessories, but this cost is usually offset compared to buying in a store because you typically don't need to pay sales tax. Compare shipping costs among online sites as they may vary. If applicable for your particular order, you might want to find out if shipping insurance is included or available as an option.

To go a step further in finding the right heart monitor for you, it might pay to ask your friends, family and colleagues if they have had any experience- either good or bad- with specific heart monitor brands or models. In addition, you should find out if any of the heart monitor brands or models has earned the endorsement or certification of any legitimate, third party entity. Finally, you may consider brand name as a criteria. Generally, the best-known and most successful businesses are those that do a good job, earn repeat business, and build a good reputation over the course of time.