The Circulatory System

A Connecticut woman is crediting her Fitbit with saving her life, after the device detected signs of life-threatening blood clots.

A look at an ancient tick preserved in amber midfeed has revealed the only known existence of an ancient red blood cell, along with the tiny parasites that infected the creature.

Vegetables are good for your health, but now there's a whole new way that one veggie could help your heart: Spinach leaves can be used as a scaffold for beating human heart cells, a new study finds.

When it comes to alcohol and heart health, the back and forth between findings can leave you feeling dizzy.

Armed with new insights into the interactions between cancer and the immune system, research teams are developing novel treatments to harness the full potential of the body's natural defenses.

Winter weather can come with a slew of health risks, ranging from heart problems to injuries from slips and falls.

Mary Tyler Moore's death on Wednesday at age 80 may highlight the long-term effects that type 1 diabetes can have on the body.

Unlike mythical vampires, vampire bats do not prey on humans — or do they?

Did Debbie Reynolds die of a broken heart?

Why do some people survive heart attacks, while others don't?

Americans' cholesterol levels are heading in the right direction, a new study finds.

As any sleep-deprived person with a mirror knows, dark circles under the eyes are usually prominent after a bad night's sleep.

Hostility is bad for heart health, and a new study shows what's going on in the body that may explain this link.

After a heart was found in a plastic bag, officials said more tests were needed to determine if the organ actually came from a human.

An 83-year-old man kept the symptoms of a genetic disease at bay — without even knowing he had it — thanks to his years of donating blood, according to a recent report of his case.

Everyone should know what to do for someone who is severely bleeding, experts say.

Drinking alcohol, even in moderate amounts, may increase the size of the heart's left atrium, a new study finds.

The effects of an irregular heartbeat can ripple across the entire body, a new meta-analysis finds.