We all know that concussions are bad for us.

It seems like common sense that a blow to the head would have negative consequences- but the damage actually happens at a really tiny level.

Concussions are often referred to as mild Traumatic Brain Injuries.

They happen when a force is transmitted to the head that leads to a collision between the brain and the skull.

Inside your skull, your brain is suspended in cerebrospinal fluid.

It looks like water and acts as a cushion for your brain.

But it doesn't protect your brain from hard impacts.

Your brain is soft tissue - it's squishy, kind of like jello.

So when you're hit with enough force, your brain hits the inside of your skull.

From the impact, your brain cells or neurons actually become deformed.

What cops most of the damage are your axons, the long fibre of the neuron that carries messages from the cell body to other cells.

Axons are like Silly Putty - they're pretty elastic and can happily jiggle around in your head day to day.

But when they're pulled rapidly-they break.

From a concussion, axons also stretch and swell.

This means they lose their elasticity; they're not as good at carrying messages to other cells or they stop sending signals altogether.

To your brain, concussions mean damage at a tiny cellular level.

To us, that means dizziness, confusion, mental fogginess, headaches and impairments in executive functioning.

When we think of concussions, a lot of people associate them with getting knocked out.

But this is a common misconception - you don't need to get knocked out to have a concussion.

The really scary thing is that some people don't even notice when they are concussed - often there are no physical symptoms, and often they don't even come from a blow to the head.

In football, for example, a hard tackle to your body can cause your brain to hit the inside of your skull.

Only one concussion can cause lasting damage.

And smaller hits, the concussions that go unnoticed or subconcussive blows, can lead to some major long term consequences.

It's hypothesized that axons stretching and deforming over and over again is linked to Chronic Traumatic Encephalopathy or CTE.

CTE is progressive brain disease that leads to a decline in memory and cognition, depression, poor impulse control and eventually, dementia.

And CTE has only been found in those with a history of repetitive brain trauma and in people as young as 27.

The damage from concussions or subconcussive blows accumulates over time and triggers the build-up of a protein called tau.

Huge amounts of tau protein live in diseased neurons as neurofibrillary tangles, like a tangled clump of string in a certain pattern throughout the brain.

If enough tau protein builds up, it blocks off pathways in the brain and leads to cell death.

Tau protein destroys brain cells.

Right now, CTE can only be diagnosed after death-these brains are stained to show you where the proteins are, and it's pretty clear to see the damage.

Hopefully more research will lead to a way to identify, treat and even cure it in life.

Research in the past 10 years has shed a lot of light on concussions in sport.

CTE was only discovered in 2005 and the National Football League didn't acknowledge that concussions had long term effects on players until 2010.

It's such a dramatic story it was released as a feature film at the end of 2015.

In September of 2015, researchers announced they had found CTE in 87 of 91 deceased NFL players they examined - that's 96% - and in 79% of all high-school, college or semi-professional football players whose brains were examined.

It is important to note that those numbers may be skewed because people donated their brains to be tested before they died, and some suspected they had the disease.

Still, concussions and mild brain trauma are a huge problem in sport and particularly American football.

Can we do anything to fix it?

First, we can improve the way that sports handle injuries.

Having ample recovery time from brain injuries is really important.

Concussion safety laws for youth sports have been adopted by all US states, where players suspected of concussions are immediately removed from games and need medical clearance for return to play.

Educating players so they can make an informed decision to play is really important too.

The accumulative effects of concussions have long term damage and, in the worst cases, can be deadly.

But even with these strategies, professional athletes still compete in these sports with a big risk to their health.

Your brain just doesn't like being thrown around!

From reoccurring trauma your brain can, kind of literally, gets its knickers in a knot.

So, what do you think?

I'm always curious to hear your thoughts so me know down in the comments or on Twitter.

And I'll see you next week.

Also, there's a super interesting series called League of Denial from Frontline, right here on YouTube.

You can click the annotation or I'll leave a link down in the description.

It's all about football and concussions and I'd highly recommend it.