Neurophysiological Mechanisms
The neurological basis for fatigue after concussion is multifactorial. Disrupted communication between the brain’s arousal systems and higher-order executive function centers likely plays a central role. Functional connectivity studies have identified abnormal activity in the thalamus and cortex, which can reduce processing efficiency, particularly during cognitive load (source).
Additionally, concussion may dysregulate neurotransmitters such as dopamine and norepinephrine, both of which are crucial to attention, energy, and motivation. The cumulative effect is a system that requires more effort to perform basic tasks, exhausting neural resources more quickly.
Circadian rhythm disturbances further compound the issue. An article in Neurology Journal outlined how disruptions to melatonin secretion post-injury can interfere with the body's natural energy cycles, perpetuating a cycle of non-restorative sleep and daytime fatigue (source).
Functional Impact in Real-World Settings
For athletic populations, especially student-athletes balancing practice, academics, and social responsibilities, fatigue can derail recovery more than physical symptoms. An athlete may clear physical exertion protocols but still be unable to maintain academic performance or social engagement due to persistent fatigue.
A study published in Scientific Reports found that chronic fatigue following concussion significantly impacts quality of life, with nearly one-third of participants showing reduced functional scores months after injury (source).
This underscores the need to treat fatigue not as a secondary symptom, but as a primary recovery barrier. Ignoring it can lead to premature return to play or return to learn, which risks re-injury or academic failure.
Objective and Subjective Measurement Challenges
One of the most frustrating aspects for both clinicians and patients is that fatigue often resists objective measurement. Unlike vestibular dysfunction or balance impairments, fatigue is largely subjective. This has led some providers to minimize its clinical relevance. However, validated self-report tools such as the Fatigue Severity Scale (FSS) and the Modified Fatigue Impact Scale (MFIS) can provide insight into symptom burden.
A systematic review in Journal of Head Trauma Rehabilitation emphasized the importance of integrating these subjective tools into post-concussion care, noting that self-reported fatigue strongly correlates with neurocognitive disruption, even when performance metrics appear normal (source).
Clinical assessment must also include screening for depression and anxiety, which frequently coexist and amplify fatigue symptoms. However, it is critical not to dismiss fatigue as “just psychological,” as doing so may delay appropriate care.
Clinical Scenarios and Application
Consider a collegiate midfielder recovering from a diagnosed concussion. After passing vestibular and exertion protocols, she returns to practice. Yet by midweek, her academic advisor reports missed assignments and difficulty focusing in class. When re-evaluated, she describes persistent mental exhaustion after short periods of reading and studying.
This case highlights a common disconnect: successful physical exertion does not equate to full neurological recovery. A phased approach to return—not just to play, but to learn—must be implemented, with specific accommodations to manage cognitive load and energy conservation. Fatigue is not a footnote in recovery—it is a central element.
Management Strategies and Interventions
Addressing post-concussion fatigue requires a multi-modal approach:
Education and Expectation Management: Athletes and families must understand that fatigue is a normal—yet complex—part of recovery. Normalizing the symptom helps reduce anxiety and promotes pacing.
Sleep Hygiene: Establishing consistent sleep routines, limiting screen time before bed, and possibly integrating melatonin under supervision may help stabilize circadian rhythms.
Graded Cognitive and Physical Activity: Progressive reintroduction of activity with close monitoring of symptom onset is key. Activities that provoke fatigue should be scaled down and reintroduced incrementally.
Environmental Modifications: Reducing sensory input (e.g., classroom lighting, noise) and limiting multitasking can preserve cognitive energy.
Referral and Collaboration: Fatigue persisting beyond three weeks may benefit from referral to a vestibular/concussion-trained physical therapist or neuropsychologist for more targeted interventions.
The BMJ Best Practice guidelines affirm that fatigue, along with drowsiness and cognitive slowing, should be treated with as much clinical weight as physical symptoms during concussion recovery (source).
Reinforcing Clinical Awareness
The reality is that many student-athletes and active adults silently endure post-concussive fatigue, often pushing through in environments that value resilience over rest. As clinicians, athletic trainers, and sports medicine professionals, it is essential to validate and address these symptoms early.
Fatigue is not a lack of effort—it is a neurophysiological response to injury.
