In order to get the best workout, you must reach your target heart rate. Your target heart rate is estimated at 60 to 80 percent of your maximum heart rate, and you get your maximum heart rate by subtracting your age from 220. So a 30 year old would have a target heart rate between 95 and 162 beats per minute.

Several machines can monitor your heart rate while exercising:

Standard Heart Rate Monitor

of the most common heart rate monitors looks like a watch but comes with an adjustable chest strap to wear while exercising. During your workout, the chest monitor relays your heart rate to the watch, allowing you to adjust your exercise intensity to best reach your target heart rate.

Strapless Heart Rate Monitor

For those who find the chest strap uncomfortable, a similar model that also looks like a watch is available. However, you must hold your index and middle fingers on the watch face for about five seconds to get a reading. This makes it difficult to get an accurate count while running, biking, swimming or taking part in almost any vigorous pursuit. You usually need to stop what you’re doing to measure your heart rate, interrupting your workout.

Heart Rate Rings

This device tracks your heart rate through a sensor on the band, so no need to wear a chest strap or pause your workout. Heart rate rings are relatively inexpensive but are not known to give the most accurate of readings, sometimes miscalculating heart rate by as much as 15 beats per minute on either end.

Heart Rate Clothing

In certain workout clothing, a transmitter is placed in a shirt or sports bra to relay your heart rate to a monitor you wear on your wrist. This option is far more costly than the other alternatives. Not only do you need to purchase the clothing but also the heart rate monitor watch, which means for less serious athletes, this option is often unnecessary.