What happens to the brain when you get knocked out?

Have you ever wondered, how does a knockout originate and what happens inside the body during those seconds? This has a scientific explanation, we could not say that it is basic, but it is not quantum physics either. 

In this post we are going to answer the question ‘’What happens to the brain when you get knocked out?’’ We took on the task of investigating what happens to the body and how it reacts to these types of situations.

What happens to the brain when you get knocked out?

When you get knocked out, your brain moves out of place, stretching axons and causing brain connections to break, turning off parts of the brain.

K.O is an acronym that refers to the Knock Out that can occur in a boxing match. This occurs when one of the two boxers provides the other with an overwhelming blow, through which the victim cannot avoid falling to the canvas.

The knock-out in boxing

The referee of the match will count to 10 to give the fallen boxer time to get up and if he does not do it, the fight is over and in that case the winner will be awarded the fight by K.O.

In the following article we will delve into the characteristics of a Knock-Out, the different types of Knock Out that exist and what the negative repercussions of reaching this instance maybe for the person who received the final blow.

Either this because he does not have more strength to get up and continue or because he has lost consciousness due to repeated blows to the head or just one of these very hard.

It is a blow that knocks out the person who receives it, that is, it makes it impossible to continue the battle agreed to a number of rounds.

It is that with the knockout the fight is finished and the winner is automatically the one who remained standing.

Counting to ten will allow the downed boxer to try to regain his energy or come to himself to continue the fight, anyway, if the ring authority notes that the boxer stands still, but staggers and without focusing on having to continue with a Pugilistic battle, this one will not allow him to continue in the fight, decreeing the Knockout.

If the blows that knocked out a boxer were within the legality allowed by boxing regulations, the winner is the one who caused the blows.

Characteristics of a KO

It is very easy to realize the characteristics of a Knock Out, especially when the physical or dexterity difference between one boxer and another is noticeable.

As the rounds go by, we will see that the weakest begins to neglect their guard and respond with less reflexes and speed to the blows, and their wobble will be more and more pronounced, so at that moment we can realize that it is very the KO is likely to be completed at any time.

What will come after all this weakening on the part of the beaten boxer?

The loss of balance and control over his actions of the boxer who receives the blows, until at a certain moment his legs will no longer resist and his body will fall, either by total weakness or by the impulse of the blow that has received.

All this is what will cause the fighter to fall to the canvas and not be able to get up, to lose the fight by K.O.

In most cases the knocked out boxer will feel disoriented and even lose consciousness for a certain time, which will vary according to the intensity of the blows received.

Not all boxing fights are as we just explained to you, in which the weakness of the person is gradual until this instance of knockout is reached. There are cases in which the knockout is sudden, due to the force of a single blow that misplaces the fighter in time and space and falls without the possibility of claiming.

There have been great boxing fights in which a fighter was clearly dominant due to the blows caused to his opponent and from one moment to the other, who was losing, propitiates an accurate blow and of such force that it dislodges who was being victorious through his effort and suddenly loses, when nobody thought about it, not even himself.

What happens to your brain when you get KO?

The Ko or Knock-out means out of combat and is a way to obtain victory in various contact sports. But do you know what exactly happens in your body when you are KO’d?

Many people think that it is caused by the intensity of the blow, but the direction from which the blow comes has a great influence. Several studies show that the skull supports stronger impacts when performed frontally than laterally.

The reason why the Ko occurs is due to the sudden internal movement that originates within the brain, when a fighter receives a blow to the head. The brain is surrounded by cerebrospinal fluid, allowing it to “float” and protect it in turn.

When the person suffers a blow, the brain collides with the walls of the bone cavity, causing the destruction of neurons. The punch the fighter receives causes the front of the skull to collide with the central lobe of the brain.

This causes neurons to “shut down” until the brain is able to fire up again. If the blow is very large, the shock of the neurons will be greater. There is then a short circuit causing confusion, disorientation, memory loss and in the worst-case loss of consciousness.

Most of the people who have been knocked out agree. A lack of memory at the time. This is known as post-traumatic amnesic syndrome, that is, the time in which a person who has suffered a head injury, cannot coherently remember what has happened both before and after the blow.

Undoubtedly, there are numerous studies that have been carried out on the consequences of the blows that fighters of various disciplines receive to the head. Muhammad Ali, one of the greatest boxers of all time, suffers from Parkinson’s. Justified by many, by the blows received to the head.

The science of knockout

To understand well what is happening you need to know 3 concepts that we will explain below. In our body there are 3 types of nervous systems (Central, Peripheral and Autonomous), at the moment we are only interested in 2 and they are the ones we are going to talk about:

  1. The Central Nervous System (CNS) is basically constituted by our brain, cerebellum and spinal cord. What is it for? Well, very simple, everything you do, say and think is thanks to this system, even the things that you do not do voluntarily, such as making your heartbeat or your stomach digest.
  2. The Peripheral Nervous System (PNS) is made up of all the nerve endings that are in our body and that connect with each other, as well as the spinal cord and later the brain.

Let’s see this system as a kind of transport of electrical impulses from outside to the brain and from the brain to our extremities. Thanks to this system, we feel pain when they hit us, burning when something burns us, pleasure when there is some stimulus that is pleasant, etc.

The impulses are carried through the nerve endings by means of electricity so that a correct stimulation of electrical impulses between the peripheral and central nerve endings creates a correct neural communication. This is known as synapses and it is thanks to this that we can carry out all the voluntary or involuntary movements that we carry out.

Knowing this, we are ready to understand what happens to the KO inside the body and why the different reactions.

When a fighter is knocked out he can react in 3 ways: falling muscle rigor, falling struck down or seizures, the latter being the least common and more complex so we will explain it in detail in another note, for now, let’s see the first 2 types.

1.- It seems that all your muscles are contracting for some reason that you are about to understand

This impressive body reaction is due to the strong trauma suffered by the head, so the SNP sends an “alert message” to the CNS that tries to make synapses so that the fighter has a correct physiological response.

But the trauma, in turn, is causing that the brain moves within the skull causing a poor interneuronal electrical communication causing an involuntary contraction of all voluntary muscles.

It can be sustained as in this case or contraction and relaxation of the same, which is called a seizure.

That is, as a direct response to the blow there is a hypercommunication between the CNS and the SNP, causing all the voluntary muscles to contract, even though the fighter is not conscious.

2.- The fighter falls completely struck down, strange breathing is also appreciated in his thorax.

The brain has 3 coatings that prevent it from directly colliding with the bones of the skull, in addition to having a fluid inside called cephalic fluid.

When a fighter receives a blow of such magnitude that his brain receives a strong contusion and at that moment there is no response from the CNS to the SNP, it is when this type of KO is originated, the fighter falls completely struck down without any type of voluntary muscular response or involuntary

That is why fighters manifest this type of breathing, with strong inspirations and expirations, this breathing is called neurological or ataxia, it seeks to re-oxygenate the brain so that it can work normally again.

In this type of KO there is also no correct electrical-neuronal response, but instead of having hyperstimulation, there is a hypo-stimulus of the SNP, which causes the fighter to fall struck down and to enter secondary defense mechanisms to help him.

Now you know how the body works when a knockout happens. While this is a cursory explanation, it is a basic summary of what happens to fighters when they suffer a loss via chloroform.

What else would you like to know from a medical point of view?

FAQS: What happens to the brain when you get knocked out?

Does getting knocked out cause brain damage?

A great movement of the brain in any direction can cause loss of consciousness in a person. The amount of time the person remains unconscious can be a sign of how bad the concussion is.

Can you die from getting knocked out?

Yes, you can die from getting knocked out.

Why does hitting your head knock you out?

The jolt damages cells in the brain walls and stretches the axons that connect neurons, destabilizing the normal flow of neurotransmitters and causing an escape of potassium ions from cells and an influx of calcium ions.

What is being knocked out?

There is a shock to the skull when a blow to the head is taken, making the brain turn about in the skull. If the brain strikes the skull wall, it triggers a temporary short-down that throws you unconscious.

How long can you be knocked out?

It depends on the head trauma magnitude. If you temporarily lose consciousness and experience a concussion, after a few months, 75 to 90 percent of people can recover completely. But for days, weeks, or even longer, significant damage to the brain will cause unconsciousness.

In this post we answered the question ‘’What happens to the brain when you get knocked out?’’ We investigated what happens to the body and how it reacts to these types of situations.

If you have any questions or comments please let us know!


Snell, R. S. (2010). Clinical neuroanatomy. Lippincott Williams & Wilkins.