What Is a Concussion?

A concussion is a mild traumatic brain injury that occurs when the brain moves rapidly inside the skull. This can happen from a direct blow to the head or from a hit to the body that causes the head to move quickly back and forth. These forces temporarily disrupt how brain cells function due to stretching and chemical changes, rather than permanent structural damage. [1][4]

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Most people do not lose consciousness with a concussion. Because the injury affects brain function rather than brain structure, concussions usually do not show up on standard imaging such as CT scans or MRI. [4–5]

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Common Symptoms of Concussion

Concussion symptoms vary from person to person and may appear immediately or develop over the hours or days following injury. Headache is the most commonly reported symptom. Other symptoms may include: [1][4]

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• Difficulty with memory, attention, or concentration

• Feeling mentally “foggy” or slowed down

• Dizziness or balance problems

• Nausea or vomiting

• Sensitivity to light or noise

• Fatigue or reduced energy

• Changes in sleep patterns

• Mood changes such as irritability, anxiety, or low mood

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Symptoms are expected to fluctuate during recovery and do not necessarily indicate ongoing damage. [1][4]

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Assessment and Diagnosis

If a concussion is suspected, early assessment by a healthcare provider is important. A concussion evaluation typically includes [2]

• A detailed history of how the injury occurred and current symptoms

• Review of previous concussions and relevant health factors (such as migraines, ADHD, anxiety, or depression)

• Assessment of neurological function, balance, eye movements, and cognition

• Use of symptom checklists to monitor severity and change over time [1][3][6]

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Brain imaging is not routinely required to diagnose a concussion and is generally reserved for situations where a more serious injury is suspected. [2][4]

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For sport-related injuries, immediate removal from play is required, with return only after medical clearance. [1][6]

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Recovery and Rehabilitation

Most people recover from a concussion within 2–3 weeks with appropriate care. Recovery timelines vary, and a smaller number of individuals may experience symptoms for longer. [1][3][7]

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Initial Rest (First 24–48 Hours)

A short period of relative physical and cognitive rest is recommended in the first day or two after injury. This involves temporarily reducing activities that significantly worsen symptoms. [1–2]

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Strict rest (complete inactivity in a dark room) is not recommended, as it may delay recovery. [2]

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Gradual Return to Activity

Current evidence supports beginning light, symptom-guided physical activity within 24–72 hours after injury. Early, controlled movement has been shown to improve recovery and reduce the risk of prolonged symptoms. [1–2][7]

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This process typically includes:

• Light aerobic activity (such as walking or stationary cycling) that does not significantly worsen symptoms

• Gradual progression of exercise intensity and duration as tolerated

• Stepwise return to school or work, with accommodations if needed

• Structured return-to-sport protocols for athletes. [1–2][7]

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If symptoms increase significantly, activity levels are adjusted rather than stopped entirely. [7]

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Rehabilitation and Targeted Support

Some individuals benefit from additional, targeted rehabilitation depending on their symptom profile, including: [3]

• Physical therapy for neck pain, balance issues, or movement intolerance

• Vestibular or vision-based rehabilitation for dizziness or visual symptoms

• Support for mood, anxiety, or sleep difficulties

• Medical management for specific symptoms such as headaches

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Care is individualized and adjusted based on progress and response to activity. [3][7]

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When to Seek Additional Medical Support

You should contact a healthcare provider if:

• Symptoms are worsening rather than improving

• Symptoms persist beyond 4 weeks. [2–3]

• You develop severe or worsening headaches, repeated vomiting, increasing confusion, weakness, or other concerning changes

• You have questions or concerns about your recovery

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Important Considerations

Children and adolescents often require a more cautious progression due to ongoing brain development. Individuals with a history of prior concussions or certain pre-existing conditions may also experience longer recovery timelines. [1][5][8]

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Education and reassurance are key components of recovery. Understanding what a concussion is, what to expect, and knowing that most people fully recover can reduce fear and support better outcomes. [1][8]