What Not to Do When You Have a Concussion

Returning to normal life too quickly after a concussion is among the most common and most harmful mistakes people make, but so is the opposite: retreating into a dark room and doing nothing for weeks. A concussion sets off a temporary energy crisis in the brain, and the activities you avoid, the substances you consume, and the way you manage rest all influence how fast that crisis resolves. Getting any of these wrong can stretch a recovery that should take a couple of weeks into one that drags on for months.

Don’t Jump Back Into Contact Sports or Intense Exercise

The single most dangerous mistake after a concussion is returning to a sport or high-risk physical activity before you have fully recovered. In a review of physician charts, roughly 44% of concussed patients returned to sport too soon, and a similar proportion went back to school prematurely, with both groups experiencing a recurrence or worsening of symptoms as a direct consequence.¹ Those numbers are striking because most people assume they can gauge their own readiness by how they feel at rest. Feeling fine while sitting on the couch does not mean the brain can handle the metabolic demands of sprinting, heading a ball, or absorbing another hit.

The catastrophic end of this spectrum is second impact syndrome. If someone still experiencing post-concussion symptoms sustains another blow to the head within the following weeks, the brain can lose its ability to regulate swelling. Diffuse cerebral edema, brain herniation, and death can follow, sometimes within minutes.² Second impact syndrome is rare, but it is almost entirely preventable. No game, practice, or workout is worth the risk of a second head injury while your brain is still recovering from the first one.

Don’t Disappear Into a Dark Room for Weeks

For years the standard advice was to rest completely until every symptom disappeared. Sit in a dark, quiet room. No reading. No socializing. No walking. This “cocoon therapy,” as researchers now call it, turns out to be counterproductive. Sustained rest from all activities after concussion is not beneficial to recovery, and evidence supports the safety and effectiveness of controlled, sub-symptom-threshold aerobic exercise.³

What does “sub-symptom threshold” mean in practice? It means exercising at an intensity that does not make your symptoms worse. A randomized trial assigned concussed adolescents to either aerobic exercise (like walking on a treadmill at a personalized pace) or a placebo stretching program starting within days of their injury. The aerobic exercise group recovered in a median of 13 days compared to 17 days for the stretching group.⁴ Four days might not sound dramatic, but when you are a teenager missing school and social life, or an adult missing work, those days add up.

The key distinction is between resting from risky activities (contact sports, heavy lifting, anything that could cause another head injury) and resting from everything. A brief period of reduced activity in the first day or two is reasonable, but withdrawing entirely from all physical and mental effort for more than a couple of days slows your recovery rather than protecting it.

Don’t Overdo Screens, But Don’t Panic About Them Either

Screen time after a concussion is one of the most confusing areas for patients and parents. The older guidance was absolute: no phones, no tablets, no television until you are symptom-free. More recent research paints a more nuanced picture that depends on timing and duration.

In the first 48 hours after injury, strict screen abstinence does seem to help. A randomized trial of concussed adolescents and young adults found that those permitted screen time during the initial 48 hours took roughly twice as long to recover: a median of 8 days versus 3.5 days for the screen-abstinent group.⁵ That is a large enough difference to justify putting the phone down for a couple of days.

After those first couple of days, however, the relationship flips from simple to surprising. A study of youth aged 11 to 17 found that moderate screen time of roughly two to four hours per day during the first three days after concussion was associated with faster symptom resolution than either very restricted use under two hours or heavy use above four hours.⁶ In other words, cutting screens to near-zero for an extended stretch may actually slow things down, perhaps because total sensory deprivation increases boredom, anxiety, and social isolation, all of which feed into symptoms. The practical takeaway: avoid screens in the immediate aftermath, then ease back in with moderate use, watching for symptom flare-ups as your guide.

Don’t Drink Alcohol

This one should be obvious but frequently isn’t, especially among college-aged athletes who feel better within a few days and assume they are in the clear. A study of NCAA athletes found that those who consumed alcohol after their concussion took about 32% longer to be cleared for return to play, averaging around 23 days compared to roughly 18 days for those who abstained.⁷ That is about five extra days sidelined, and the effect held after adjusting for other factors like concussion severity.

Alcohol’s interference probably works through several channels. It disrupts sleep quality, increases dehydration, and impairs the brain’s metabolic recovery process. It also raises the risk of falls and additional injuries during a period when balance and reaction time are already compromised. If you are recovering from a concussion, treat alcohol like contact sports: completely off the table until you have been formally cleared.

Don’t Neglect Sleep

A concussion disrupts the brain’s normal sleep architecture, and those disruptions can persist well beyond the first few days. Changes in sleep have been documented in the acute, sub-acute, and chronic phases of recovery, and poor sleep can prolong symptom resolution, worsen cognitive performance, and destabilize mood.⁸ The irony is that many concussed individuals find it harder to fall asleep or stay asleep at exactly the time their brain needs rest the most.

The mistakes to avoid here are both active and passive. Actively, do not stay up late scrolling your phone, consuming caffeine in the evening, or keeping irregular hours. Passively, do not assume that fragmented, low-quality sleep is just something you have to power through. Good sleep hygiene becomes a genuine treatment tool after a concussion: consistent bedtimes, a cool and dark room, and avoidance of stimulants in the hours before sleep. If sleep problems persist beyond the first couple of weeks, it is worth raising with your doctor, because untreated sleep disruption can become a self-sustaining cycle that keeps other symptoms alive.

Don’t Drive Before You’re Ready

Driving requires rapid decision-making, divided attention, and precise motor coordination, exactly the capacities that a concussion temporarily weakens. Research has found that reaction times behind the wheel remain slowed even after concussion symptoms have clinically resolved.⁹ This is one of the most underappreciated risks of concussion. Feeling subjectively “fine” does not mean your brain processes road hazards at the same speed it did before the injury.

There is no universal guideline specifying how many days to wait before driving again, and this ambiguity is part of the problem. Many people get back in the car within days, often because they have no other way to get to work or medical appointments. If you must drive during recovery, keep trips short, avoid highways and night driving, and be honest with yourself about whether your reaction time and concentration feel truly normal or just tolerable.

Don’t Catastrophize, But Don’t Ignore Symptoms Either

Psychology plays a larger role in concussion recovery than most people realize, and there is a real balancing act between two opposite mistakes. The first is catastrophic thinking: convincing yourself that the injury has permanently changed your brain, that you will never feel normal again, that every headache is proof of lasting damage. Research has found a strong association between catastrophizing thoughts and persistent post-concussion symptoms, with catastrophizing at three months after injury being the single strongest correlate of ongoing symptoms.¹⁰ The same study found that depression at three months was significantly linked to symptom burden at six months, creating a vicious cycle where fear of symptoms leads to avoidance, which leads to deconditioning and isolation, which worsens symptoms.

The opposite mistake is to dismiss every symptom as no big deal, push through, and refuse to modify your activity. That path leads to the premature return-to-play problems discussed earlier. The healthiest approach is somewhere in the middle: take the injury seriously, modify your activities as needed, but do not interpret normal recovery fluctuations as evidence that something is permanently wrong. Most concussions resolve within two to four weeks. If yours doesn’t, that warrants a follow-up with a specialist, not a spiral into fear.

Be Cautious With Caffeine

Coffee and energy drinks are deeply woven into daily routines, and cutting them cold turkey after a concussion can cause withdrawal headaches that are hard to distinguish from concussion symptoms. But continuing to consume caffeine at your usual level is not straightforwardly safe either. In experimental brain injury research, caffeine has shown both beneficial and harmful effects depending on the dose, timing, and context. It can enhance alertness and reduce mental fatigue, which might help with the cognitive sluggishness many concussion patients experience. At the same time, studies have found that caffeine consumers report higher somatic discomfort, and heavy use during adolescence and early adulthood may interfere with normal brain remodeling processes when combined with repetitive mild head injuries.¹¹

The practical guidance here is frustratingly dose-dependent. A single cup of coffee in the morning is probably fine for most adults recovering from a concussion, and abruptly stopping caffeine may do more harm than good if it triggers withdrawal. But pounding energy drinks or relying on caffeine to mask fatigue and push through your day works against the recovery process. If you were a heavy caffeine user before the injury, taper gradually rather than quitting outright, and keep your intake to moderate levels.

Don’t Fly Too Soon After a Concussion

Air travel introduces a variable most people never think about: reduced cabin pressure, which means less oxygen reaching the brain. Research on traumatic brain injury in military contexts has shown that early exposure to a hypobaric environment, the kind of reduced-pressure atmosphere found in aircraft cabins, increases the neuroinflammatory response and the severity of secondary brain injury.¹² The brain after a concussion is already dealing with ionic imbalances and metabolic stress; layering mild hypoxia on top of that is not ideal.

There is no universally agreed-upon waiting period before flying after a concussion, and the evidence is drawn largely from animal models and military evacuation studies rather than commercial aviation research. Still, the biological rationale is clear enough to warrant caution. If you can avoid flying in the first few days after a concussion, that is the safest approach. If travel is unavoidable, staying well hydrated, avoiding alcohol in flight, and being prepared for a temporary worsening of headache or fatigue are all sensible measures.

Don’t Ignore Your Balance and Dizziness

Dizziness and balance problems are among the most common concussion symptoms, and they are also among the ones most likely to be brushed off as minor. Post-concussive vestibular dysfunction involves complex interactions between the inner ear, the central nervous system, and the neck, and it often gets worse rather than better when ignored.¹³ Avoiding all environments that trigger dizziness might seem logical, but that avoidance prevents the brain from recalibrating its balance systems. Vestibular rehabilitation, a structured program of exercises designed to challenge and retrain balance, is one of the more effective treatments for persistent dizziness after a concussion.

The mistake here is twofold. Some people avoid any movement that makes them dizzy, which delays vestibular recovery. Others push through severe dizziness without professional guidance, risking falls and worsening anxiety around physical activity. If dizziness or balance problems persist beyond the first week or two, a referral to a vestibular therapist is more productive than hoping it resolves on its own.

Don’t Skip the Cognitive Return-to-Learn Steps

Returning to school or cognitive work too aggressively is just as risky as returning to sports too soon, even though it does not carry the same dramatic risks of a second impact. After a concussion, both physical and cognitive activities place additional metabolic demands on a brain that is already struggling to meet its normal energy needs, potentially causing symptoms to reemerge or worsen.¹⁴ For students, this means that sitting through a full day of classes, taking notes, and studying for exams can be as symptom-provoking as running laps.

A graduated return-to-learn plan mirrors the graduated return-to-play protocol used in sports. You start with short periods of cognitive activity, like 20 to 30 minutes of light reading, and increase gradually as tolerated. Accommodations like extended test deadlines, reduced homework loads, and permission to take breaks during long classes are not luxuries; they are part of the medical management of the injury. The same applies to adults returning to demanding cognitive work. If you spend your day in front of spreadsheets or writing code, a full eight-hour day within the first week is likely too much.

Know the Red Flags That Require Emergency Care

Most concussions resolve without dramatic complications, but a small percentage of head injuries that initially look mild are masking something more serious, like bleeding inside the skull. Emergency department assessment begins with identifying red flags that need immediate intervention, such as traumatic intracranial hemorrhage.¹⁵ You should seek emergency care if you experience any of the following after a head injury:

• Worsening headache: A headache that steadily intensifies over hours rather than staying stable or improving.
• Repeated vomiting: Nausea is common after a concussion, but vomiting more than once suggests increased intracranial pressure.
• Seizures: Any seizure activity after a head injury warrants immediate evaluation.
• Confusion or disorientation that worsens: Mild confusion right after the injury is expected, but increasing confusion over time is a red flag.
• Weakness or numbness: Especially on one side of the body, which could indicate a focal brain injury.
• Slurred speech: Difficulty speaking that develops or worsens after the initial injury.
• Loss of consciousness: Particularly if it lasts more than a few seconds or occurs after an initial period of seeming fine.

These signs can appear hours after the initial injury, which is why someone with a concussion should not be left alone for the first 24 hours. The idea that you need to wake a concussed person every hour through the night is somewhat outdated, but having someone nearby who can recognize deterioration and call for help is still sound advice. A concussion is a clinical diagnosis, and objective measures of impairment remain valuable for catching problems that a patient’s subjective self-assessment might miss.¹⁶ When in doubt, getting checked out is always the right call.