Heart rate monitor
- This article refers to a device used by laypersons. For the article on the medical device performing a similar function, see Electrocardiography.
A heart rate monitor is a device that allows a user to measure their heart rate in real time. It usually consists of two elements: a chest strap transmitter and a wrist receiver (which usually doubles as a watch). Strapless heart rate monitors are available as well, but lack some of the functionality of the original design. Advanced models additionally measure heart rate variability to assess a user's fitness.
The chest strap has electrodes in contact with the skin to monitor the electrical voltages in the heart (see electrocardiography for more details). When a heart beat is detected a radio signal is transmitted, which the receiver uses to determine the current heart rate. This signal can be a simple radio pulse or a unique coded signal from the chest strap; the latter prevents one user's receiver from using signals from other nearby transmitters (known as cross-talk interference).
There are a wide number of receiver designs, with all sorts of advanced features. These include average heart rate over exercise period, time in a specific heart rate zone, calories burned, and detailed logging that can be downloaded to a computer.
The Polar Electro company's website states they invented the first accurate, wireless electrocardiogram heart rate monitor in 1977, to be used as a training tool for the Finnish National Cross Country Ski Team. [1]
In December 2005, Textronics Inc. introduced the first garment with integrated heart sensors in the form of a sports bra.[citation needed] Special materials in the sports bra sense heart rate from the body and transmit it to a wrist receiver. The garment provides a comfortable alternative to the chest strap.
Today, the same concept of heart rate training is used by world-class athletes such as Olympic Gold Medal Winner Melanie Valerio as well as everyday people.[citation needed]