The beat goes on

Learn when, how, and why you should keep track of your heartbeat.

Soon after you wake up tomorrow morning, before you even sit up in bed, take your pulse. It's fairly easy if you have a clock or timer nearby (see "Measuring your heart rate"). Known as your resting heart rate, this value ranges from 60 to 100 beats per minute in most adults.

"To get a good sense of your resting heart rate, check it every few mornings over the course of several weeks," advises cardiologist Dr. Aaron Baggish, director of the Cardiovascular Performance Program at Harvard-affiliated Massachusetts General Hospital. It's best to measure your resting heart rate when you've been getting your typical amount of sleep and exercise and aren't feeling ill or dehydrated.