Your resting heart rate can tell you about your fitness and stress.

Everybody has natural rhythm. Call it your inner drummer--the heartbeat keeps time for the rest of the body. But what happens if your beat's too fast or slow? In medical terms, that's called cardiac ...

Sleep bradycardia is a slow heart rate during sleep. It may be a natural, healthy sleep response or a sign of an underlying health issue. Most healthy adults have a heart rate between 60 and 100 beats ...