2.5 billion. No, it's not how old the Earth is. It's the average amount of times the heart beats in a lifetime, according to the American Heart Association. A quick review on this important organ: The ...

Normal Slow Walking Heart Rate Causes of Faster Heart Rate Measuring Heart Rate How to Lower Heart Rate When to See a Doctor You may know your target heart rate when working out or your ideal heart ...

In this era of fitness trackers, we have easy access to our heart rate at any given moment. Every so often, a number catches your eye as it flashes on your Garmin or Apple Watch while you're sitting ...