Quick Answer
A concussion occurs when your brain is jarred inside your skull - usually from a direct blow to the head, face, or neck, or from a forceful impact to the body. This sudden movement can temporarily disrupt how your brain functions, leading to symptoms such as headache, confusion, dizziness, and memory problems.
Understanding the Mechanics
When a concussion occurs, the brain experiences sudden movement that temporarily disrupts how nerve cells communicate and how the brain manages energy. While the brain usually recovers fully, these changes explain why symptoms occur. Key effects include:
- Temporary brain cell disruption: Nerve cells may not fire or communicate normally, affecting thinking, memory, and coordination.
- Chemical imbalances: Shifts in important brain chemicals can contribute to headaches, dizziness, or sensitivity to light and noise.
- Increased energy demands: The brain works harder to restore balance, which can lead to fatigue, "brain fog," and slower thinking.
- Blood flow changes: Concussion can temporarily alter blood flow, affecting how well different areas of the brain function.
- Subtle structural effects: Even if standard CT or MRI scans look normal, tiny changes in brain connections and pathways may occur, contributing to lingering symptoms.
- Inflammatory response: The brain may trigger mild inflammation, which can affect recovery and contribute to ongoing symptoms.
It's Not About "Blacking Out"
A common misconception is that you must lose consciousness to have a concussion. In reality, most concussions happen without any loss of consciousness. You can sustain a concussion while remaining fully awake and aware.
Common Causes
Concussions can happen in many situations:
- Sports activities - Contact sports like football, hockey, soccer, and basketball
- Motor vehicle accidents - Car crashes, even at low speeds
- Falls - Slipping on ice, falling from a ladder, or playground accidents
- Physical assault - Any direct blow to the head or body
- Blast injuries - Military personnel may experience concussions from explosions
What Makes It Serious?
While often called a "mild" brain injury, concussions should always be taken seriously. The temporary disruption in brain function can:
- Affect your ability to think clearly and process information
- Impact memory, concentration, and decision-making
- Cause physical symptoms that interfere with daily activities
- Increase vulnerability to further injury if not properly healed
The Importance of Proper Care
Every concussion is unique, and recovery varies from person to person. Some people feel better within days, while others may experience symptoms for weeks or months. Professional assessment and guided recovery are essential to:
- Ensure accurate diagnosis
- Monitor for complications
- Develop a personalized recovery plan
- Safely return to work, school, sport, and daily activities
Key Takeaways
- A concussion is a mild brain injury caused by rapid movement of the brain inside the skull
- You do not need to black out to have a concussion
- Symptoms can be physical, cognitive, emotional, or sleep-related
- While usually temporary, concussions require proper medical care
- Most people recover fully with appropriate rest and gradual return to activities
When to Seek Help
If you suspect a concussion, it's important to:
- Remove yourself from activity immediately
- Obtain a medical diagnosis from your GP or Nurse Practitioner
- Seek care and rehabilitation from a concussion clinic or healthcare provider trained in concussion management
- Monitor for red flag symptoms that require emergency care (see related article)
Need professional guidance? Book an assessment with one of our clinicians at Shift Concussion Management in Guelph, Ontario, or locate a trained Shift Concussion provider near you.
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Article authored by Kailin Walter, DC, Director of Program Development at Shift Concussion Management. Last updated January 2025.