Depending on your age, level of conditioning, and your fitness goals, you should train in a particular heart-rate zone. Beginners should attempt elevating their heart rate to 50%-60% of their predicted maximum (220-AGE) while intermediates and advanced should aim for 70%-85% of their maximum. The higher your heart rate, the more calories you will burn (and more FAT calories) and the more fit you will become. To calculate your maximum heart rate, simply subtract your age from 220 beats per minute (bpm). For example, if you're 30 years old, you would have a maximum heart rate of 190bpm. Achieving 70% of your maximum heart rate, you would be working at a heart rate of approximately 133 beats per minute (0.7 x 190bpm). You can also use a heart rate monitor for instant feedback about your heart rate or count how many times your heart beats per minute by finding your carotid (neck) or radial pulse (wrist) and counting (beats per minute) in 10-second increments and then multiply by six.