Training Heart Rate Target new and updated by world-famous artist Bruce Algra presents four heart rate zones to train at. The reason why there are four zones(versus only one on the older heart rate poster) is to allow individuals with different fitness levels and goals to train at their appropriate heart rates. For example, a person who is out of shape should probably train in the fat-burning zone, while a person who is in excellent shape should probably train in the aerobic zone. Vital information on selecting the zone that is best for you is presented in an easy to follow and colorful layout