The heart is the body's hardest-working muscle. Whether you're awake or asleep, or exercising or resting, your heart is always at work. It pumps blood through arteries to deliver oxygen to organs and ...

Your heart is a muscular organ that helps circulate your blood, which delivers oxygen and nutrients to your tissues. There are four chambers and four valves in your heart, and each ensures proper ...

Science writer Mary Roach is fascinated by the human body, especially, she says, the "gooey bits and pieces of us that are performing miracles on a daily basis." Take the human heart, for instance. If ...

In heart failure, the heart can no longer supply the body with enough blood. The condition often develops over many years, ...