October 19, 2022

5 Surprising Facts About Blood

Key Takeaways

  • Blood makes up nearly 7% of your body’s weight. 
  • Despite advances in medical and healthcare technology, there is no substitute for human blood.
  • “Pregnancy glow” in pregnant women is due to the blood supply increasing by 50%. 
  • The cornea is the one place in your body where there are no blood vessels.

Blood is one of the most important and vital fluids in the human body. It’s so important that  scientists and healthcare professionals are constantly researching and discovering new and exciting information about blood. As recently as October 2022, scientists even discovered a new blood type, the ‘Er’ group. 

However, that’s just the tip of the iceberg. We’ve put together a list of five surprising facts about blood that you may not know.

1. Blood types were discovered in 1901 

The first successful blood transfusion occurred in England in 1665. Granted, it was between two dogs, but this early success helped pave the way for the first successful human blood transfusion 130 years later in 1795 by Dr. Phillip Physick (although, he didn’t publish his findings). 

What’s really remarkable about these early medical breakthroughs? The fact that blood types hadn’t even been discovered. 

The discovery of blood types didn’t occur until 1901 by Austrian scientist Dr. Karl Landsteiner. Initially, Dr. Landsteiner only discovered three types: A, B, and O blood groups. A year later he discovered the AB blood group that today comprises the four blood groups we know today as the ABO blood group system.

Today, there are actually around 30 different recognized blood types (or blood groups), but A, B, AB, and O are the most common. 

Bonus fact: The most common blood type in the United States is O positive, with 39% of the population. AB negative is the least common blood type with only 0.5% of the population.

2. There’s more blood in your body than you realize

Here’s a trivia question: What percentage of your body’s weight is from your blood? 

While you think it over, your body is a factory that is constantly producing and replacing old red blood cells with new ones. In one ounce of blood, there are about 150 billion red blood cells. This amounts to about 2.4 trillion red blood cells in one pint of blood. In fact, the human body manufactures nearly 17 million red blood cells per second. If needed, the body can even produce 7 times that amount (or 119 million per second). 

At any given moment, the total number of red blood cells in an adult human can number as much as 20-30 trillion. All of these red blood cells have to weigh something, so how much of your body’s weight is from blood?  

Answer: Blood makes up about 7 percent of your body’s weight. 

Bonus fact: 15% of your body weight is from your bones. 

3. Pregnant women get an extra boost of blood 

Pregnancy is an exciting and sometimes scary time. With all the changes that a person’s body goes through, from hormones and skin changes, to a growing belly and much more, it’s no wonder that a pregnant woman’s blood supply also increases. 

By the 20th week of pregnancy, the amount of blood in a pregnant woman’s body will have increased by 50%. That’s why you often hear of women experiencing a “pregnancy glow”, or a rosy complexion that occurs during pregnancy due to increased blood circulation. 

The body produces more blood during pregnancy to provide extra blood flow to the uterus and other organs, especially the kidneys. After all, it takes a lot of energy and nutrients to grow a new human! 

4. There is no substitute for blood

Humans are fairly inventive - especially when it comes to healthcare innovation. In fact, we’ve gone as far as creating a number of unique solutions to enhance or replace different body parts and functions. The artificial heart is a great example. First successfully implanted in a human in 1982, the artificial heart is designed to replace an ailing heart. There’s even ongoing research aimed at creating other organs, including an artificial bladder, kidneys, pancreas, and more. 

So, have we created a substitute for human blood? 

Despite these advances in healthcare technology, there is still no substitute for human blood. There are many reasons that make creating artificial blood a challenge, but the biggest hurdle is that human blood is made up of a lot of complex parts that each serve a specific function. Reproducing each of these functions properly is extremely challenging.  

That’s not to say a breakthrough can’t or won’t occur at some point in the future, but only time will tell. 

5. There’s one place in your body where blood isn’t present 

Although blood is arguably one of the most important fluids in our body, that still doesn’t mean it’s everywhere. In fact, there is actually one place in your body where blood vessels aren’t present - the cornea (eye). 

You might be asking yourself, “But how does the cornea receive oxygen if blood isn’t present to deliver it?” That’s because the cornea values transparency for vision, and blood vessels would prevent that. Instead, the cornea receives nutrients from the tears and aqueous humor (a fluid in the anterior portion of the eye).  

Bonus Fact: Get at-home blood testing with Getlabs 

Blood is one of the most important and vital fluids in your body. That’s why nearly 70% of medical decisions rely on accurate blood test results. If these five facts didn’t surprise you, then maybe this bonus fact will: Blood testing does not need to be performed in a lab, it can be done at-home with mobile phlebotomy services like Getlabs. 

Getlabs comes directly to your home or office and collects lab samples to deliver to Labcorp or Quest for testing. 

If you have questions about how it works, simply visit Getlabs FAQ to learn more, or schedule your next appointment by following the link below. 

This page is provided for educational and informational purposes only and does not constitute the provision of medical advice or professional services. The information provided should not be used for diagnosing or treating a health problem or disease, and those seeking personal medical advice regarding any of the tests and conditions referenced above are advised to consult with a licensed clinician. Always seek the advice of your qualified health provider regarding a medical condition and do not disregard professional medical advice or delay in seeking it because of any information on this page. If you think you may have a medical emergency, immediately call 911 or go to the nearest urgent care center or hospital.

Book an at-home lab collection

Getlabs sends a nearby medical specialist to you to collect your labs for Labcorp and Quest. Available same-day, nationwide.

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