Your body recycles approximately 30 million red blood cells every minute.

Red blood cells, also known as erythrocytes, have a typical lifespan of about 120 days in the human body. As they age, their membranes become rigid and fragile, making it difficult for them to navigate the narrowest capillaries. The spleen serves as the primary site for erythroptosis—the programmed death and removal of these aging cells.Within the spleen, blood passes through the red pulp, which contains narrow passages called splenic sinusoids. Healthy, flexible red blood cells can deform their shape to squeeze through these gaps. However, older cells that have lost their elasticity become trapped and are subsequently engulfed by specialized immune cells called macrophages.This recycling process is incredibly efficient at salvaging vital nutrients. Macrophages break down the hemoglobin from the trapped cells into heme and globin. The heme is further processed to release iron, which is then transported back to the bone marrow by a protein called transferrin. This iron is essential for the production of new hemoglobin for the next generation of red blood cells.According to hematology studies, the bone marrow must produce roughly 2 to 3 million new red blood cells every second to maintain a stable count. This means your body is constantly balancing the destruction of 30 million cells per minute with an equal rate of production. This precise equilibrium ensures that an adult's blood contains approximately 20 to 30 trillion red blood cells at any given time.