A concussion is a functional brain injury resulting from biomechanical forces, causing a temporary disruption of normal brain processes. The medical approach to concussion recovery has undergone a significant transformation. Current medical consensus no longer supports the traditional mandate of strict, prolonged rest as the sole treatment. Instead, controlled, sub-symptom aerobic exercise has emerged as a therapeutic tool to facilitate recovery and reduce the risk of persistent symptoms. This shift emphasizes active management, moving away from outdated protocols.
Transitioning from Rest to Active Recovery
The initial step in concussion management still involves a brief period of relative rest, typically limited to the first 24 to 48 hours following the injury. This short window allows the brain to manage the immediate metabolic crisis caused by the injury. During this time, activities of daily living are generally permitted, provided they do not significantly worsen symptoms.
Extended periods of strict physical and cognitive rest, however, are now understood to be counterproductive to recovery. Prolonged isolation and inactivity can lead to secondary issues such as physical deconditioning, increased anxiety, depression, and social withdrawal. These factors can complicate and delay the resolution of concussion symptoms, creating a cycle of dysfunction.
The transition to active recovery requires medical clearance and begins when the patient can tolerate everyday activities without a substantial increase in symptoms. The goal is to introduce light physical activity early, as research indicates this can speed up recovery time and reduce the chances of developing post-concussion syndrome.
Physiological Benefits of Controlled Activity
Controlled aerobic activity aids brain healing by directly addressing the physiological dysfunctions caused by the injury. A concussion disrupts the brain’s ability to regulate its own blood flow, a state known as cerebral blood flow (CBF) dysregulation. Sub-symptom threshold exercise helps to restore this normal CBF and metabolic function, ensuring the brain receives the necessary oxygen and glucose for repair.
Exercise also plays a role in promoting neuroplasticity, the brain’s ability to reorganize itself by forming new neural connections. Physical exertion stimulates the production of neurotrophic factors, such as Brain-Derived Neurotrophic Factor (BDNF). BDNF supports the survival of existing neurons and encourages the growth of new synapses, which is fundamental to nerve repair and cognitive function.
A concussion can cause dysregulation of the autonomic nervous system (ANS), which controls involuntary functions like heart rate and blood pressure. This autonomic imbalance contributes to common symptoms such as headaches, dizziness, and exercise intolerance. Carefully monitored aerobic exercise acts as a targeted therapy to help reset the ANS, normalizing heart rate and blood vessel response, and alleviating these lingering symptoms.
Guidelines for Graded Aerobic Exercise
The primary principle of graded aerobic exercise is finding the individual’s symptom threshold: the level of exertion that does not significantly worsen symptoms. This threshold is unique to each person and must be identified to ensure a safe exercise prescription. The exercise should be light and avoid any risk of contact, collision, or falls, making activities like stationary biking or walking ideal.
A standardized assessment, such as the Buffalo Concussion Treadmill Test (BCTT), is often used by clinicians to objectively determine this safe exertion level. The test establishes a target heart rate that the patient can maintain without a significant increase in concussion symptoms. The exercise program should then be performed at a heart rate approximately 80 to 90% of the maximum heart rate achieved before symptom worsening during the test.
The exercise protocol involves a gradual, step-wise increase in intensity and duration over time. A common starting point is a 15- to 20-minute session of light aerobic activity performed five to six days a week. If symptoms temporarily increase during the activity, they must return to baseline within a short period, typically less than one hour, for the exercise to be considered safe. If symptoms are exacerbated and persist, the activity level must be immediately reduced to the previous tolerated level, and the progression must be slowed.