What Happens in Your Brain During a Concussion
Your brain floats in cerebrospinal fluid inside the skull. A concussion occurs when a force — direct blow or rapid acceleration/deceleration — causes the brain to move within the skull, stretching and damaging brain cells. This is a functional injury (disruption of cell chemistry), not a structural one — it does not show on CT or MRI scans.
The damaged cells release potassium and glutamate, triggering an energy crisis as the brain desperately tries to restore normal ion balance. Blood flow may temporarily decrease just when energy demand is highest. This metabolic mismatch is why symptoms persist for days to weeks — the brain needs time to restore its chemical balance. A study in the British Journal of Sports Medicine found that brain metabolism remained abnormal for up to 30 days after concussion even when symptoms had resolved.
Recognizing a Concussion — You Do Not Need to Lose Consciousness
Fewer than 10 percent of concussions involve loss of consciousness. Symptoms can appear immediately or develop over hours. Physical: Headache (most common), dizziness, nausea, balance problems, blurred vision, light and noise sensitivity, fatigue. Cognitive: Feeling foggy or slowed, difficulty concentrating, memory problems, confusion. Emotional: Irritability, sadness, nervousness, mood swings. Sleep: Sleeping more or less, difficulty falling asleep.
In children, symptoms may present differently: excessive crying, loss of interest in activities, unsteady walking, eating and sleeping changes. Young children cannot articulate what they feel — behavioral changes after head impact should be taken seriously.
A 17-year-old soccer player headed the ball during a game and felt dizzy for 30 seconds. She continued playing. By evening she had a severe headache, could not concentrate on homework, and felt nauseous. She did not connect her symptoms to the earlier header until her mother asked about it. She had a concussion — without ever hitting the ground, without losing consciousness, and without realizing what had happened.
Red Flags — Go to the ER Immediately
While most concussions resolve without complications, certain symptoms suggest a more serious injury requiring emergency evaluation: worsening headache that does not improve. Repeated vomiting. Seizures. One pupil larger than the other. Increasing confusion or agitation. Slurred speech. Weakness or numbness in limbs. Loss of consciousness lasting more than 30 seconds. Inability to recognize people or places.
After any suspected concussion, someone should monitor the person for the first 24-48 hours. It is safe to sleep after a concussion, but someone should check periodically for worsening symptoms.
Recovery — Active Rest, Not Complete Rest
Most adults recover within 10-14 days. Children may take up to 4 weeks. The current approach has evolved from complete rest to active recovery. After 24-48 hours of relative rest, light activity below the symptom threshold is now encouraged — walking, gentle stationary cycling. A study in the British Journal of Sports Medicine found that prescribed aerobic exercise beginning 2 days after concussion actually accelerated recovery compared to strict rest.
Return to school/work: gradual, starting with reduced hours. Return to sport follows a stepwise protocol: rest → light aerobic exercise → sport-specific exercise → non-contact drills → full contact practice → game play. Each step requires 24 hours symptom-free before progressing. Never return to play on the same day as injury.
Post-concussion syndrome — symptoms persisting beyond expected recovery — affects 10-30 percent of patients. Persistent headaches, depression, anxiety, concentration difficulty, and sleep disturbances may require specialized treatment. Repeated concussions before the first heals carry serious risks including prolonged recovery and, in rare cases, second impact syndrome.
