What your heart monitor is trying to tell you.

Kids and tweens today aren’t getting enough exercise. You may think of their attachment to electronic gadgets as a big part of the problem, but two fitness experts explain why one gadget in particular — a heart-rate monitor — may be an important part of the solution.

Knowing your maximum heart rate is essential for effective aerobic workouts. But if you're using 220 minus your age, you may be missing the mark entirely.

Feel like your fitness regimen is stalling? Grab a heart-rate monitor for instant feedback and lasting motivation.