How much blood do we actually need to stay alive?

At the sight of it, this bodily fluid might make you feel nauseous, lightheaded or downright sick. But regardless of how it makes you feel, we all need it to survive.

We’re talking about blood!

How much blood do you have in your body? Why is it so essential to your survival And how much blood can you lose before it’s too late?

Blood is the most important fluid in your body. Why do you think vampires want it so badly? It flows throughout your body via the cardiovascular system. Along its route, your blood circulates red blood cells, which distribute oxygen, and white blood cells that defend against infection. The average person has about 4.7 to 5.5 liters (1.2 to 1.5 gallons) of blood. So, how much of it can you lose? The answer? A lot.

Whether it’s from a minor scrape or a major injury, we lose a lot of blood in a lifetime. The technical term for bleeding is called a hemorrhage, which occurs after a blood vessel ruptures and blood escapes from it. A hemorrhage can happen inside or outside of our bodies.

Most of the time, our bodies are pretty amazing at healing. Whenever you happen to get a cut, you can heal yourself without even having to go to the hospital. Through a process known as coagulation or clotting, your blood changes from a liquid into a gel. This forms a blood clot, which stops the bleeding to give your body time to recover. But you can’t do that all the time. If you ruptured a major artery, like the jugular vein in your neck, you would lose a lot of blood at an alarming rate.

For an injury like this, there are 4 levels of blood loss. The first stage involves losing 10 to 15 percent of your blood. If this happens, you luckily won’t feel many effects, besides maybe some lightheadedness. Even when you go to donate blood, you’re giving approximately 8 to 10 percent of it in just one sitting. And all you need to recover is a cookie and some juice!

The next level would be losing 15-30 percent of your blood. That’s nearly one to two liters, or about enough to fill a large Coke bottle. At this stage, your skin will cool, and you’ll be feeling weak with your heart beating faster than ever in order to keep you alive.

After you lose a bit more blood, at just below 40 percent, you will most likely need a blood transfusion. But it’s not over for you yet. You might still be alive, but your heart will be beating extremely fast. Smaller blood vessels will constrict, helping to keep blood pumping throughout your body.

And after you lose over 50 percent of your blood or 2.75 liters on average, then you’ll be in a comatose state. Your heart will stop beating, and it won’t be able to fuel your organs, causing them all to fail. But, if you receive rapid medical treatment, then you actually have a chance of surviving, although it is unlikely. Beyond that, if you were to lose anymore, well, you can kiss that cookie and juice goodbye as you won’t be around to enjoy either of them!

But don’t worry! There’s no need to raise your blood pressure! Your body is resilient, and your blood regenerates. So give a little, lose a little, your body can handle it.