Running extreme distances may strain more than just muscles and joints. New research suggests ultramarathons can alter red ...

Your blood is a delicate mixture. Researchers and clinicians often use blood to learn what's going on inside our bodies, in part because siphoning off a tube of blood is easier and less painful than ...

Extreme endurance running damages red blood cells in ways that may affect their ability to function properly, according to a ...

Red blood cells carry oxygen from the lungs around the body. They then carry carbon dioxide from around the body back to the lungs. These cells are an important component of blood. However, a range of ...

Red blood cells transport oxygen throughout your body, including to vital organs and tissues. They also help your body get rid of carbon dioxide. Too little or too many red blood cells may be ...