Where does this come from, and can I check it?

Red blood cells circulate for about 120 days before being recycled. The figure is taken from NIH, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a human body fact?

Yes. It sits on the Human Body shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

The body produces millions of red blood cells every second

Red blood cells circulate for about 120 days before being recycled

Bone marrow manufactures roughly two to three million red blood cells every second to replace aging cells. These disc-shaped cells travel through the vascular network for about 120 days, carrying oxygen via haemoglobin molecules before liver and spleen macrophages dismantle them.

Where this comes from

NIH

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An average adult body contains about five litres of bloodBlood accounts for roughly seven to eight percent of total adult body weight Capillary walls are only one single cell layer thickThin vascular walls enable rapid diffusion of oxygen and metabolic nutrients White blood cells defend the body against infectious pathogensLeukocytes circulate in blood and tissue to destroy invading bacteria and viruses The human heart beats over one hundred thousand times dailyPumping continuously the heart propels thousands of litres of blood every day Platelets initiate blood clotting to seal broken blood vesselsCell fragments clump together and form fibrin meshes to stop bleeding Blood plasma is composed of over ninety percent waterThe liquid portion of blood transports proteins glucose hormones and electrolytes

Tags: blood, cells, circulation

The body produces millions of red blood cells every second: the short answers

Where does this come from, and can I check it?: Red blood cells circulate for about 120 days before being recycled. The figure is taken from NIH, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a human body fact?: Yes. It sits on the Human Body shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.