15 Facts about Human Blood

#1 Blood makes up around 7-8% of the weight of a human body.¹⁾http://www.sciencekids.co.nz/sciencefacts/humanbody/blood.html

The average amount of blood in your body is an estimate because it can depend on how much you weigh, your sex, and even where you live. Sometimes the amount of blood in the human body can differ based on where you live. For example, people who live at high altitudes have more blood because there isn’t as much oxygen at higher altitudes.

#2 There are 150 Billion red blood cells in one ounce of blood. ²⁾https://www.cbco.org/blood-fun-facts/

Red blood cells are cells that carry oxygen which contain hemoglobin and it is the hemoglobin which permits them to transport oxygen (and carbon dioxide).

• There are 2.4 Trillion red blood cells in one pint of blood.
• About 50-75 trillion cells in the body and half of these are red blood cells.
• The human body manufactures 17 million red blood cells per second. If stress precipitates a need the body can produce up to 7 times that amount. (That’s up to 119 million red blood cells per second.)
• A red blood cell is around 7 microns in size. (A micron is one millionth of a meter).
• It takes about 30 seconds for a red blood cell to circle the entire body.

#3 It only takes 20 to 60 seconds for a drop of blood to travel from the heart, through your body, and back to the heart again.

#4 Nearly half the population is blood type O and can donate blood to people with all other blood groups but can only receive Type O themselves. ³⁾https://www.cbco.org/blood-fun-facts/

#5 The blood you donate is sold on the open market and it’s a US$4.5 billion per year industry. ⁴⁾https://www.forbes.com/sites/erincarlyle/2012/06/27/blood-money-the-guys-who-trade-your-blood-for-profit

#6 One pint of donated blood can save up to 3 lives. ⁵⁾Fact Slides http://www.factslides.com/s-Blood

#7 Different kinds of animals have different kinds of blood. Dogs have 4 blood types; cats have 11; cows have about 800. ⁶⁾https://www.infoplease.com/math-science/biology/human-body/blood-types

#8 The most common blood type in the United States  is O Positive (39% of the population),   while the least common blood type is AB negative with only (0.5% of the population). ⁷⁾https://www.cbco.org/blood-fun-facts/

#9 All blood isn’t red. Crabs have blue blood. Earthworms and leeches have green blood. Many invertebrates, such as starfish, have clear or yellowish blood. The blood is blue because it contains a copper-based respiratory pigment called hemocyanin. ⁸⁾https://dnr.maryland.gov/ccs/Pages/horseshoecrab-medical.aspx

#10 If you lose more than 40 percent of your blood, you will die. ⁹⁾https://www.healthline.com/health/how-much-blood-in-human-body#howmuch-blood-can-you-lose

This is about 2,000 mL, or 0.53 gallons of blood in the average adult.

Your blood pressure and heart rate will stay close to normal as you lose up to 30 percent of your blood, or up to 1,500 mL of blood (0.4 gallons). After losing this amount of blood, you will experience the following:

• You’ll start to have a rapid heart rate higher than 120 beats per minute.
• Your blood pressure will drop.
• Your breathing rate will go up.

#11 Blood is three times thicker than water and the average person has between nine and 4.5-6 litres (12 pints) of it in their body.

#12 Red blood cells make 250,000 trips around the body during their four-month lifespan. ¹⁰⁾https://health.howstuffworks.com/human-body/parts/facts-about-the-human-body.htm

#13 Every second about eight million blood cells die and another eight million are formed. ¹¹⁾https://www.cbco.org/blood-fun-facts/

#14 The rarest type of blood is AB and is present in about 4 per cent of the population. these people can receive all types of blood. ¹²⁾https://www.cbco.org/blood-fun-facts/

#15 The lifespan of white blood cells ranges from 13 to 20 days, after which time they are destroyed in the lymphatic system. ¹³⁾ http://www.rnceus.com/cbc/cbcwbc.html