There are fair number of people who have taken up bicycle riding as a means to exercise and strengthen their heart. For them, a primary concern is, "how much work is my heart doing, while I exercise?" The relevant part of "How fast it is beating?", should be looked at against your age, weight and possible medical infirmities. Taken a step further, you might want to let a device know a "range" or "Target zone" of heartbeats per minute that were plotted against time, so that you wouldn't exceed safe limits while you were trying to achieve fitness.
With heart rate monitors, you receive a table, based on weight and age, to help you determine these parameters. A physician would be able to assist you, as well. Ideally, once you started the device, it would tell you how long your warm-up period was, your cool-down period, and (the most important part) how long you stayed working in the "target zone" doing quality work for your heart. This amount of time in the "target zone" is the number you would want to improve on. Naturally, this heart rate device should be wireless.
The Polar heart rate monitors are well recognized as the HRM of choice, by people in the know everywhere. Cateye will soon enter the heart rate monitor field and their work is highly regarded. The Polar Favor, Edge, and Pacer models are produced in Hong Kong, while the Accurex and Vantage are made in Finland. Each comes with a performance program booklet that helps you establish the parameters for your own personal workout, based upon your interests, weight control, general fitness. The booklet includes diagrams and tables, to establish your program based on known weight, age and gender tables.
All of the Polar heart rate monitors rely on a chest strap, which the transmitter snaps onto, in the front of your body. The strap is held in place with firm, stable elastic bands. The transmitter has two sensors, one at each side of your chest, to pick up your heart beat. The sensors are placed below each side of your breast. The transmitter itself, is on the front of the water tight transmitter assembly. Beginning in the fall of 1992 Polar started shipping their HRM units with a new one-piece design, un-openable transmitter. The previous design permitted the back of the transmitter to be removed with a jewelers screwdriver to replace the internal lithium battery. The new model, though completely sealed, is without the oportunity to replace the battery in the "field" because the transmitter, sensors, and battery are molded into a the one-piece plastic assembly. The new design is said to have achieved a much longer useful battery life, due to improvements in the electronic design of the transmitter and reduced current draw. When the transmitter's internal battery fails the entire chest sensor/transmitter unit, (not the strap) must be replaced. To be fair, this sealed unit design has a higher reliability over time than the previous model. The wireless broadcast and heart monitoring functions are of these devices amazingly sophisticated. We found the transmitter and receiver could be no more than 5 feet from each other to properly receive a steady signal.