The RS800CX watch is the ultimate training computer for running athletes.

As a heart rate monitor, the RS800CX works by first checking your daily condition, and then guiding you to the ideal training intensity for your age and fitness level. Knowing your heart rate not only helps you reach your personal fitness goal, but also improves your physical condition in general, as it's vitally important to train at the appropriate intensity level. If you exercise too hard, you may quit before you reach the real benefit, but if you work out too leisurely, you'll struggle to lose weight at all.

The RS800CX helps overcome these problems by encouraging you to map out a complete fitness routine. The watch also displays heart rate info in several ways, including as a percentage of your maximum heart rate, as beats per minute, and within a graphical target zone indicator. And should your heart rate exceed or dip below your target zone, the RS800CX will sound an alarm that helps you return to form.