💊Daily Pill: What is Your Hematocrit?

Your oxygen-carrying capacity

The Daily Pill is a series of short posts where I share the definition of a daily term I think you should know. Read it every morning and build up your medical vocabulary.

🩸Hematocrit:

Blood is made up of two main components: plasma (the liquid part), and cells (white blood cells, platelets, and red blood cells). Red blood cells carry oxygen from the lungs to the rest of the body and return carbon dioxide to the lungs. You take a blood sample, spin it down in a centrifuge, and the percentage of volume occupied by red blood cells at the bottom compared to the rest of the sample is your hematocrit (~45%). The lower your hematocrit is, the less red blood cells your have, and hence, the lower your oxygen-carrying capacity. If it gets too low, you are anemic. Training and exercise - particularly at high altitudes, increase your hematocrit.

🧠Trivia:

• We make about 2 million red blood cells per second.

• Blood doping enhances athletic performance by artificially increasing an athlete's hematocrit and is typically done in one of three ways:

  • Transfusion: Either by re-infusing the athlete's own blood (autologous transfusion) or using someone else's blood (homologous transfusion).

  • Erythropoietin (EPO) Use: Injecting the hormone that stimulates red blood cell production, to elevate red blood cell counts.

  • Synthetic Oxygen Carriers: These are substances that can carry oxygen, used to enhance oxygen transport in the blood, similar to red blood cells.