TRAIN SMARTER WITH THE NEWEST HIGH-TECH HEART RATE MONITORS
Whether you are just starting a fitness program or are an experienced athlete, you can greatly benefit from paying attention to your heart rate during exercise. Heart rate serves as a window into the body, giving you minute-to-minute feedback on your physical condition based on all the factors affecting it--exercise intensity, diet, temperature, humidity, altitude, fatigue, and more.
Total Heart Rate Training explains:

-Heart function during exercise
-How heart rate monitors...