How many liters of blood does the human body have?

The amount of blood in the human body is usually equivalent to 7% of body weight. The average amount of blood in your body is just an estimate because it depends on your weight, your gender, and even where you live.

There is an estimated 5 liters of blood in the average adult human body but this number will vary depending on various factors. During pregnancy, a woman can have up to 50% more blood volume.
Sometimes, the amount of blood in the human body can be different depending on where you live. For example, people who live at high altitudes have more blood because there is less oxygen at high altitudes.
The amount of blood in a person's body will depend on their age and size. Losing a certain amount of blood will not harm the body. Blood volume to body weight:
Approximately 7 - 8% of an adult's body weight. Approximately 8 - 9% of a child's body weight. Approximately 9 - 10% of a newborn's body weight. An average person's blood count is as follows:
Newborn: A full-term baby has about 75 milliliters (mL) of blood per kilogram of body weight. If a child weighs about 3.6kg, they will have about 270ml of blood in their body. Children: An average child weighing 36kg will have about 2,650 mL of blood in his body. Adults: The average adult weighing between 65 and 80kg should have about 4.5 to 5.7 liters of blood. Pregnant women: To support the developing fetus, pregnant women typically have 30 to 50% more blood volume than non-pregnant women.

Your doctor usually won't directly measure the amount of blood you have because they can estimate it based on other tests. For example, a blood test called a hemoglobin and hematocrit test can estimate how much blood is in your body relative to how much fluid is in your body. Your doctor can then look at your weight and your water retention level. All of these factors can indirectly measure how much blood you have.
If you have had a major injury that causes blood loss, doctors will often use your weight as a starting point to predict how much blood you have. They will then use factors like your heart rate, blood pressure, and breathing rate to estimate how much blood may have been lost. They will also try to monitor additional blood loss (if any) so that it can be quickly replaced with a blood transfusion.
Doctors can use this test to evaluate many different conditions, such as:
Congestive heart failure . CKD . Shock . There are different tests, but a blood volume test usually involves injecting a small amount of a tracer into the body. The healthcare professional will then use imaging technology to monitor the blood moving throughout the body.

According to the American Red Cross, the standard amount of blood that a person will give in a blood donation is 450ml. This is about 10% of the blood in your body, and it's still safe to lose that much blood.
A person may feel a little dizzy after donating blood. Therefore, blood donation centers ask blood donors to rest for 10-15 minutes and drink water before leaving.
If a person gets sick or has an accident, they can lose more blood. This can lead to shock and threaten their lives.

Heavy bleeding can be dangerous. In medical terms, shock means not enough oxygen reaches the tissues in the body. Low oxygen levels can damage the brain and other organs.
If someone loses blood, the body will start directing blood to vital organs and no longer supply blood to the skin, fingers or toes. A person who has lost blood will likely begin to turn pale or feel numbness in the extremities. When a person loses about 15% of their blood volume, they may begin to go into shock, although their blood pressure and other signs may then remain normal.
After losing 20 - 40% of blood, the person's blood pressure will start to drop and they start to feel anxious. If they lose more blood, they will start to feel confused. Their heart rate can increase to about 120 beats per minute as the body tries to maintain blood supply to vital organs.
When 40% or more blood is lost, the patient will go into severe shock. Their heart rate will rise above 120 beats per minute. They may go into a coma and may lose consciousness.

Bleeding can be external or internal, but both types can lead to shock.
External bleeding: Head or deep wound or cut on/near a vein; such as on the wrist or neck, can lead to severe blood loss. Internal bleeding: An internal injury, such as a blow to the abdomen, can lead to sudden and significant blood loss. However, it may not be visible from the outside. Laboratory tests can help find the cause and location of internal bleeding. For example, a cloudy ulcer, lung cancer or a ruptured ovarian cyst, can also cause internal bleeding. Depending on the location of the internal bleeding, bruising may begin to appear. You may lose blood through your mouth, nose, or other openings.

A person with severe bleeding will need medical attention.
For external bleeding, the person should:
Sit or lie down. Elevate the injured part, if possible. Apply pressure to the wound to slow the bleeding, or have someone else do it. Call 911 immediately if:
Severe bleeding. Bleeding that doesn't stop or slows down when pressure is applied. Severe bruising on the body or head. There is a change in consciousness or difficulty breathing.

A blood transfusion is a medical procedure to replenish blood for someone who has lost blood. Reasons for needing a blood transfusion may include:
Loss of blood. Have a disease that affects the amount of blood in the body, such as cancer or anemia. A blood transfusion can be a life-saving procedure for someone who has lost blood. People may also receive other parts of blood, such as plasma and platelets, for different treatment purposes.

Your body makes about 2 million red blood cells every second. Blood cells are made from stem cells in the bone marrow. Stem cells are cell types that can give rise to other types of cells. This process goes on continuously throughout a person's life.
Blood is composed of different parts:
Red blood cells transport oxygen and carbon dioxide. White blood cells help protect the body against disease and infection. Platelets help stop bleeding. Plasma helps transport solutes through the blood and supports the immune system. It takes about 24 hours for the body to replace the lost plasma, but it takes up to 4-6 weeks to replace the lost red blood cells.
Red blood cells get their color from hemoglobin, which contains iron. It can take several months for iron levels to return to normal after blood loss or blood donation. People who have lost blood due to donation or other reasons can be compensated by:
Drink lots of water. Consume foods rich in iron, such as beef liver and fortified foods.

The circulatory or cardiovascular system is responsible for transporting blood throughout the body. In this system, the heart pumps blood to the blood vessels, which deliver blood to the organs of the body. There, the blood supplies oxygen and other nutrients.
Other systems and organs that play an important role in maintaining blood levels in the body are:
Kidneys : Regulates the fluid balance in the body. Skeletal system: Because bone marrow makes blood cells. Nervous system: Allows other systems to complete their tasks. If anything goes wrong with these systems/organs, the amount of blood in the body can be altered, oxygen supply and a person's ability to survive will also be affected. About 7 - 8% of an adult's body weight is blood. The body can easily replace a small amount of lost blood, making blood donation easy. But if a person loses about 15% or more of their blood volume, there may be a risk of shock. Therefore, if you have signs of significant internal or external bleeding, seek medical help immediately.
In addition, regular health check-ups are extremely important. With basic blood tests, it is possible to monitor health status as well as detect blood diseases early. You always need to be aware of unusual symptoms so that you can get medical attention early.
Unit of Hematology and Cell Therapy - Vinmec Times City International General Hospital is a prestigious address for examination and treatment of blood diseases. Established on September 3, 2019, Unit has the role of providing intensive medical care for patients with benign or malignant hematological diseases, by means of chemotherapy, cellular immunotherapy. , hematopoietic stem cell transplantation, autologous immune boosting therapy,...

References: medicalnewstoday.com, livescience.com, healthline.com