Living with concussion

What is a concussion?

A concussion is a traumatic brain injury caused by a bump, blow, or jolt to the head, or by a hit to the body that causes the head and brain to move rapidly back and forth. This sudden movement causes the brain to bounce or twist inside the skull, stretching and damaging brain cells and triggering a cascade of chemical changes that can take weeks or months to resolve.

Concussion is classified as a mild traumatic brain injury (mTBI), but "mild" refers only to the fact that it is rarely life-threatening. It does not mean the effects are minor. For many people, they are anything but.

It is also worth noting: a concussion does not require a direct blow to the head. Any force strong enough to whip the head rapidly, including a hit to the body, a car accident, or a fall, can cause the brain to move inside the skull with enough force to trigger the injury. The movement is the mechanism, not the contact point.

What actually happens in your brain

Most people are told they have a concussion without anyone explaining what that actually means at a cellular level. Understanding it helped me enormously. It made my symptoms make sense, and it changed how I thought about recovery.

The brain sits inside the skull, cushioned by cerebrospinal fluid. It is soft tissue, roughly the consistency of firm jelly. When the head accelerates and decelerates rapidly, the brain experiences inertial forces, and the axons, the long, thread-like fibres that connect neurons to each other, get stretched and sheared. This is called diffuse axonal injury. It does not show up on a standard CT or MRI. The brain can look completely normal on a scan while this disruption is happening at a microscopic level. This is one of the most important things to understand about concussion: invisible does not mean not real.

The chemical storm

The stretching of axons opens up tiny pores in the cell membrane. Through those pores, potassium floods out of the cell while calcium and sodium flood in. This rapid exchange of ions triggers widespread, haphazard firing across neurons, which also releases a flood of an excitatory chemical called glutamate. Glutamate causes even more neurons to fire. The result is a kind of chemical storm: a wave of disorganised electrical activity spreading through the brain. This is the excitatory phase of concussion, and it is partly why people feel disoriented, confused, or strange in the immediate aftermath of an impact.

The energy crisis

After the storm, the brain urgently needs to restore its normal chemical balance. To do this, it activates energy-hungry pumps to push calcium and sodium back out of cells and pull potassium back in. This process burns enormous amounts of ATP, which is the brain's energy currency. At the same time, blood flow to the brain is reduced, meaning less glucose is arriving to be converted into energy. The brain is demanding more fuel precisely when less is being delivered. The result is a metabolic energy crisis that research suggests can last up to 30 days in humans. This is why you feel exhausted. Not tired. Exhausted. The brain is working flat out just to stabilise itself.

The calcium influx creates a second problem. It gets stored in the cell's mitochondria, which impairs their ability to produce ATP efficiently. The brain is forced to switch to a backup system that produces nine times less energy, while demand is at its highest.

Why symptoms can outlast the initial injury

There is also a network-level effect. In a healthy brain, you switch fluidly between two modes: a resting "default mode" network when you are not focused on anything in particular, and an "executive network" when you need to concentrate on a task. After concussion, research using fMRI shows that both networks can activate simultaneously. Because the brain cannot switch cleanly between them, it burns more energy to perform even simple tasks, and cognitive fatigue sets in quickly. This is why a conversation, a supermarket, or reading a page of text can feel completely overwhelming in ways that are very hard to explain to people who have not experienced it.

A tour of the brain: what gets affected and how

The brain is not a single organ doing a single job. It is a collection of regions, each responsible for specific functions, connected by a dense web of neural pathways. Concussion tends to affect the whole brain through that diffuse axonal injury, but certain areas are more vulnerable than others, and understanding which ones can help explain why your particular symptoms are the way they are.

Frontal lobe

Located directly behind the forehead, the frontal lobe is the most exposed part of the brain and one of the most commonly affected in concussion. It controls executive function: planning, decision-making, concentration, emotional regulation, and impulse control. It is also closely tied to personality and identity. When the frontal lobe is disrupted, people often find it harder to organise thoughts, manage frustration, or feel like themselves. The version of you that used to plan ahead and hold things together can feel like it has gone somewhere else.

Temporal lobes

The temporal lobes sit on either side of the brain, roughly behind the ears. They handle auditory processing, language comprehension, short-term memory, and mood regulation. Temporal lobe disruption can produce difficulty finding words mid-sentence, sensitivity to noise, memory gaps, and mood instability that feels out of character.

Hippocampus

Nestled deep in the temporal lobes, the hippocampus is the brain's memory centre. It is responsible for forming new memories and retrieving existing ones. Concussion-related disruption here is why people struggle to retain new information, forget things they knew well, or feel like information just does not stick the way it used to.

Cerebellum

Located at the lower back of the brain, the cerebellum coordinates movement, balance, posture, and processing speed. It also works in tandem with the frontal lobe on judgment and impulse control. Disruption here shows up as balance problems, coordination difficulties, dizziness, and a feeling that the body is slightly out of sync with itself.

Brainstem

The brainstem connects the brain to the spinal cord and controls the body's most fundamental functions: heart rate, breathing, reflexes, alertness, and sleep cycles. It is also the relay station between the brain and every system in the body. When the brainstem is affected, people can experience dysregulation in sleep, autonomic nervous system function, and the basic sense of feeling safe and settled in the body.

The corpus callosum

This band of nerve fibres connects the brain's left and right hemispheres and allows them to communicate. It is frequently affected in concussion and diffuse axonal injury. When communication between the hemispheres is disrupted, the cognitive load of ordinary tasks increases, and processing speed slows. Things that used to happen automatically start to require effort.

The neck: the injury most people do not know they have

This is the section I wish I had read years earlier. It changed how I understood my own recovery, and it is consistently under-discussed in standard concussion management.

Any force strong enough to cause a concussion is strong enough to injure the neck at the same time. The same rapid acceleration and deceleration that shakes the brain also strains the soft tissues, ligaments, joints, and muscles of the cervical spine. It is almost impossible to sustain a concussion without some degree of neck involvement. Yet the neck is rarely assessed, and when it is not assessed, its contribution to ongoing symptoms is invisible.

The problem is that cervical injury produces symptoms that look exactly like post-concussion syndrome: headaches, dizziness, brain fog, fatigue, cognitive difficulty, and sensory sensitivity. If the neck is driving those symptoms and no one is treating the neck, the symptoms will not resolve, regardless of how much rest or cognitive rehabilitation someone does.

Why the neck matters so much

The upper cervical spine, the top two vertebrae where the skull meets the neck, houses and protects the lower portion of the brainstem. It also carries the vertebral arteries, which supply blood to the brain. When the cervical spine is strained or misaligned, several things can happen at once: blood flow to the brain is affected, the brainstem's regulatory functions are disrupted, and the nerves that supply the face, scalp, and head are compressed or irritated.

There is also a structure called the trigeminocervical nucleus, a relay station in the brainstem where pain signals from the upper cervical spine converge with signals from the head and face. This is why tight or injured muscles in the neck and base of the skull can produce headaches that feel like they are coming from inside the head, when they are actually coming from the neck. Post-traumatic headaches are often treated as migraines when the pattern suggests they are cervicogenic, meaning originating in the neck, and therefore would respond to cervical treatment rather than migraine medication.

Fascia: the tension that holds everything together, and apart

Fascia is the connective tissue that wraps around muscles, organs, nerves, and bones throughout the body, forming a continuous web from head to foot. It does not have sharp boundaries. The fascia of the scalp connects to the fascia of the neck, which connects to the fascia of the shoulders and upper back. When impact occurs, that tension ripples through the whole system.

After a concussion or whiplash-type injury, fascial tension in the scalp, sub-occipital region (the base of the skull), jaw, and neck is extremely common. This tension can compress nerves and blood vessels, restrict the normal movement of the cerebrospinal fluid that cushions the brain, and contribute to a persistent sense of pressure or tightness in the head that does not respond to standard pain relief. It also contributes to a heightened sensitivity in the whole system, where the nervous system is already overloaded, and every additional input feels louder than it should.

This is one of the reasons that treatments addressing the whole fascial system, including craniosacral therapy, myofascial release, and certain forms of physiotherapy and osteopathy, can be meaningful in concussion recovery when standard approaches have plateaued.

Symptoms: what you might actually experience

The standard symptom list includes headaches, dizziness, nausea, fatigue, and sensitivity to light and noise. But the fuller picture is wider than that. People with concussion often describe:

• Cognitive fog: difficulty finding words, losing thoughts mid-sentence, forgetting familiar things
• Emotional dysregulation: irritability, tearfulness, or emotional responses that feel disproportionate
• Sleep disruption: difficulty getting to sleep, staying asleep, or feeling rested even after long sleep
• Anxiety and low mood: often underreported and under-treated as part of concussion management
• Sensory sensitivity: overwhelm in busy environments, difficulty with screens, noise intolerance
• Neck pain, jaw tension, and headaches that feel like they live inside the skull
• Balance problems and a feeling that the body is slightly out of sync
• Personality and identity changes: feeling like a different person, or feeling like the capable version of yourself has gone somewhere else
• Hormonal disruption: changes to energy regulation, mood, and menstrual cycles that are often not connected to the concussion by the treating clinician

That last one, the identity shift, is among the least discussed and most destabilising aspects of serious concussion recovery. When your capacity to do the things that define you is suddenly gone, the question of who you are becomes urgent and painful in a way no symptom checklist captures.

What helps

Early management matters. The old advice of complete rest in a dark room has largely been replaced by guidance toward graded return to activity: doing a little more each day as symptoms allow, rather than waiting for full resolution before doing anything. Complete physical and cognitive rest for longer than 24 to 48 hours is no longer considered best practice.

After that initial window, the evidence supports a layered approach. Vestibular physiotherapy for dizziness and balance has strong support. Cervical assessment and treatment should be part of any recovery that is not progressing as expected. Sleep management is foundational. Nervous system regulation, through breathwork, vagal toning, and stress reduction, supports the brain's healing environment. Nutrition, particularly anti-inflammatory approaches, plays a supporting role. Addressing psychological symptoms early rather than waiting is increasingly recommended.

What does not help: pushing through symptoms, returning too quickly to full cognitive or physical load, using alcohol, and ignoring signs that recovery is stalling. All of these are common. All of them delay recovery.