What happens to the brain in a concussion?

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Last updated: July 4, 2025View editorial policy

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From the Guidelines

A concussion is a mild traumatic brain injury that occurs when the brain rapidly moves back and forth inside the skull due to a blow, bump, or jolt to the head or body, causing a temporary disruption in normal brain function, as stated in the 2024 American Heart Association and American Red Cross guidelines for first aid 1. When a concussion occurs, the brain experiences a sudden movement that causes brain tissue to change shape, stretching and damaging brain cells and creating chemical changes. These changes lead to a temporary energy crisis in the brain, as damaged cells require more energy to repair while blood flow may be reduced.

Symptoms of Concussion

Symptoms typically include:

  • Headache
  • Confusion
  • Memory problems
  • Balance issues
  • Sensitivity to light and noise
  • Sometimes loss of consciousness These symptoms can be categorized into physical, cognitive, emotional, and sleep-related symptoms, as outlined in the American Academy of Pediatrics clinical report on sport-related concussion in children and adolescents 1.

Recovery and Management

Recovery usually requires physical and cognitive rest for 24-48 hours, followed by a gradual return to normal activities.

  • Physical rest is essential to prevent exacerbation of symptoms and allow for continued recovery 1.
  • Cognitive rest is also recommended to prevent worsening of symptoms, which may include a temporary leave of absence from school or reduction of workloads 1. Most concussions resolve within 7-10 days, though some may take longer, especially in children and adolescents.

Persistent Postconcussion Symptoms

However, some individuals may experience persistent postconcussion symptoms (PPCS), which can include a combination of physical, cognitive, and emotional symptoms, as discussed in the JAMA Network Open article on nonpharmacological treatment of PPCS in adults 1. If symptoms worsen or include severe headache, repeated vomiting, seizures, or increasing confusion, immediate medical attention is necessary as these may indicate a more serious brain injury. The management of concussion and PPCS requires a comprehensive approach, including early information and advice, graded physical exercise, vestibular rehabilitation, and interdisciplinary coordinated rehabilitative treatment, as recommended in the Danish Health Authority's National Clinical Guidelines 1.

From the Research

Concussion and Brain Effects

  • A concussion is a type of mild traumatic brain injury that results in symptoms within the physical, cognitive, emotional, and sleep domains 2.
  • The brain effects of a concussion can be significant, with symptoms including headache, dizziness, and difficulty concentrating 3, 4.
  • Cognitive and physical rest are recommended to allow symptoms to resolve, with a gradual introduction of light-to-moderate intensity aerobic exercise thereafter 2.

Rest and Recovery

  • Rest is considered the best immediate treatment for concussion, with the goal of reducing symptoms and promoting recovery 5.
  • However, the optimal duration and type of rest are still debated, with some studies suggesting that strict rest may not be necessary 6.
  • A period of 24-48 hours of rest immediately following concussion, followed by gradual introduction of aerobic exercise, may be beneficial for recovery 2.
  • Cognitive rest may require temporary school absence and/or a modified class work or homework load to allow symptoms to resolve 3.

Treatment and Management

  • Various interventions, including pharmacotherapy, light aerobic activity, graded exercise treadmill test, hyperbaric oxygen therapy, vestibular physiotherapy, and cervical spine manual therapy, have been evaluated for their effectiveness in treating concussion symptoms 4.
  • Aerobic exercise has been shown to be safe and potentially beneficial for concussion recovery, with participating in aerobic exercise below the point of symptom exacerbation being safe in both the acute and chronic post-concussion symptom stages of recovery 2.
  • Further research is needed to evaluate the long-term outcomes of rest and treatment, as well as to determine the optimal timing and intensity of aerobic exercise for concussion recovery 4, 2.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Efficacy of aerobic exercise following concussion: a narrative review.

Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme, 2023

Research

Sport-related concussion: Evaluation and management.

Paediatrics & child health, 2014

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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