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 ...

Carley is a writer, editor and social media professional. Before starting at Forbes Health, she wrote for Sleepopolis and interned at PBS and Nickelodeon. She's a certified sleep science coach and ...

Danielle Kosecki is an award-winning journalist who has covered health and fitness for 15 years. She's written for Glamour, More, Prevention and Bicycling magazines, among others, and is the editor of ...

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 ...