Concussions: Recognizing the Symptoms

By 4Football Staff · September 21, 2026 · 11 min read

What a concussion is, the signs coaches and teammates can see, the symptoms players feel, the danger signs that mean an emergency, and what to do the moment you suspect one.

A running back lowers his shoulder, gets hit from the side, and pops back up. He jogs to the huddle, but he lines up in the wrong spot and asks the quarterback what the play is. Nobody saw him lose consciousness, he says he feels fine, and the next snap is about to start. What happens in the next ten seconds can matter more than anything else in the game.

That scene is hypothetical, but every coach, parent and teammate should recognize it. Most concussions do not look like the knockouts that appear in movies. They are quiet, easy to miss and easy to hide, and the player is often the last person to realize something is wrong. Knowing the signs is the first step toward getting an injured player out of the game before a second hit makes things worse.

This article is general education about concussion recognition. It is not medical advice and cannot diagnose anyone. If you suspect a concussion, the player should be removed from play and evaluated by a licensed health care professional.

What a concussion is

A concussion is a type of mild traumatic brain injury. It is caused by a blow to the head, or by a hit to the body that makes the head and brain move rapidly back and forth. Inside the skull, the brain is cushioned by fluid, but a sudden jolt can still stretch and disturb brain cells and temporarily change how the brain works.

The word "mild" is misleading. It describes the injury's usual outlook compared with more severe brain injuries, not how it feels. A concussion can disrupt thinking, balance, vision, mood and sleep. It is usually not visible on standard imaging such as a CT scan or an MRI, which is why diagnosis relies on a careful clinical evaluation of symptoms, memory, balance and thinking rather than a single test.

A few facts help clear up common confusion:

• A helmet does not make a player concussion-proof. Helmets are designed mainly to reduce the risk of skull fractures and serious head injuries. Our article on helmet technology and standards explains what a helmet can and cannot do.
• Loss of consciousness is not required. Most people who have a concussion are never knocked out.
• A direct hit to the head is not required. A hard tackle to the torso or a fall that snaps the head can cause one.
• Symptoms can be delayed. Some appear minutes later, and others show up hours or even the next day.

Signs observers can see

A sign is something other people can observe. Coaches, officials, teammates, parents and athletic trainers watch for these behaviors after any impact:

• Looking dazed, stunned or vacant
• Moving clumsily or losing balance, such as stumbling or reaching for something to hold
• Answering questions slowly or repeating questions
• Forgetting an instruction, a play, the score or the opponent
• Lining up in the wrong position or running the wrong route
• Being unable to recall events before or after the hit
• Showing a sudden change in mood or behavior, such as irritability, sadness or inappropriate laughing
• Loss of consciousness, even briefly
• Holding the head or appearing to be in pain
• Slow to get up after contact

Any one of these after a significant hit is a reason to stop and look closer. Players often cannot see these signs in themselves, which is why teammates and staff need to be on watch. Many leagues now teach coaches and officials to call an injury timeout whenever they notice any sign.

Symptoms the player feels

A symptom is something only the player can report. The usual categories are:

Players do not always describe their problems in medical language. A younger child might say "my head feels funny," "I feel weird," "the lights are too bright" or "I can't see right." A teenager might just say they are tired. Coaches and parents should encourage players to report anything unusual rather than waiting for a perfect description.

Why players hide symptoms

Understanding why concussions go unreported helps coaches and parents create a safer culture. Players hide symptoms because they:

1. Do not want to let teammates down in an important game
2. Worry about losing a starting spot or a scholarship opportunity
3. Think a headache is part of football
4. Do not recognize the symptoms as a sign of injury
5. Fear being seen as soft

Coaches set the tone. A team that praises players for speaking up, and for pulling a teammate out of a game, will find more injuries early. A team that rewards toughness at all costs will find fewer injuries, but only because players stop reporting them. Rules in every state now push in the same direction, as described below.

The "when in doubt, sit them out" rule

Nearly every health and sports organization uses a version of one simple rule: if a player might have a concussion, the player does not return to the game or practice that day. The rule exists because a suspected concussion cannot be ruled out by watching a player walk around or by asking one question.

The reasons are practical:

• The brain is vulnerable after an injury. A second impact before recovery is complete can prolong symptoms, and specialists continue to study a very rare but serious pattern of dangerous brain swelling after a second blow in young athletes.
• Symptoms may worsen after a short delay. A player who seems fine on the sideline can feel much worse an hour later.
• Playing while impaired creates other risks. A dizzy or slowed player is more likely to suffer another injury, such as an ankle sprain or a collision, because reaction time is reduced.

Every state and the District of Columbia has some form of youth sports concussion law. The details vary, but they usually require education for coaches, parents or athletes, removal of a suspected player from play, and written clearance from a health care professional before the player returns. The first law of this type was passed in Washington State and is commonly named after a young football player, Zackery Lystedt. Check your state's rules with your school district or state athletic association.

Danger signs that mean call for help

Most concussions are not life-threatening, but a small number of head injuries involve bleeding or swelling inside the skull. The following signs call for emergency care. In the United States, dial 911 or go to the nearest emergency department:

• One pupil larger than the other
• Being extremely drowsy or unable to be awakened
• A headache that gets worse and does not go away
• Slurred speech, weakness, numbness or decreased coordination
• Repeated vomiting or nausea
• Convulsions or seizures
• Unusual behavior, increasing confusion, restlessness or agitation
• Loss of consciousness lasting more than a brief moment
• Any neck pain, numbness or tingling along with a head injury, because a neck injury may be present

If a player is down and not moving, do not move him. Treat the situation as a possible neck injury and wait for trained responders. This is part of the emergency action plan every team should have written down in advance.

What to do in the first few minutes

A simple sequence helps coaches and parents who feel rushed on the sideline.

1. Stop play. Call the player out. Do not let a player finish a drive or a rep.
2. Do not leave the player alone. Someone should stay with him and watch for worsening signs.
3. Get a qualified person involved. At many high school and college games, an athletic trainer or team physician is present. In youth games, there may be no one with medical training, which is why a written plan and an emergency contact are important.
4. Use a recognized tool if you are trained to. Medical professionals use standardized sideline instruments such as the Sport Concussion Assessment Tool (SCAT), which checks symptoms, memory, concentration and balance. These tools are for trained examiners and are not a way for a parent to rule out an injury.
5. Tell the parents or guardians. Give them the facts and the warning signs that need follow-up.
6. Arrange a medical evaluation. A concussion is diagnosed by a health care professional.
7. Do not let the player return that day. No one should be sent back into the game after a suspected concussion, regardless of how he feels.

The NFL's approach is a useful model for how structured these procedures can be. At league games, independent medical personnel, including a neurotrauma consultant who is not employed by either team, have a role in the evaluation of suspected head injuries. Our article on the NFL concussion protocol lays out how that process works. You can follow the league's reported injury statuses on our injury report page, though what a team lists is determined by the club and league, not by this site.

What the next 24 to 72 hours look like

After a suspected concussion, doctors often recommend a short period of reduced activity followed by a gradual return to normal life. The detail of the plan belongs to the player's clinician, but the general pattern is useful for families to know:

• Watch for changes. Symptoms may change over the first day or two. Worsening headaches, vomiting, increasing confusion or unusual drowsiness mean calling the doctor or returning to the emergency department.
• Do not keep a player awake all night on a rigid schedule unless a clinician says so. Sleep is a normal part of recovery, and families should follow the clinician's advice about checking on the player.
• Limit screens and mental strain if they bring on symptoms. Concentrating hard at school, reading or using a phone can worsen symptoms for some players.
• Avoid activities that risk another hit. Bikes, trampolines and rough play all carry a risk of another head injury.
• Plan for school. Many players need temporary adjustments, such as extra time or reduced workload, before they feel normal again.

Recovery time varies. Many adults recover within a couple of weeks, and children and teenagers often take longer. Some people take much longer, and every injury is different. Our article on return-to-play protocols after a concussion explains the stepwise process that follows once symptoms improve.

Recognizing concussions in younger players

Children and teenagers deserve special attention because they are less likely to describe what they feel and more likely to want to keep playing. Youth coaches, who often have the least medical support, should be especially watchful.

• Young children may not have the vocabulary for dizziness or fogginess. Watch for crying without an obvious reason, a sudden loss of interest in play, clinging to a parent, unusual clumsiness, or a change in how the child eats or sleeps.
• Teenagers often minimize symptoms. They may say they are fine because they know what the answer means for their playing time. Asking "Does anything feel different than it did before the hit?" works better than "Are you okay?"
• Everyone may show symptoms away from the field. A parent might notice a child who is irritable at dinner, struggling with homework that was easy last week, or unusually sensitive to the noise of a television.

Because a coach cannot see these later changes, parents and teachers are part of the safety net. A short note from a coach to a parent after any significant hit, even one that seemed minor, gives the family a reason to watch for delayed signs. Many leagues require this kind of notice, and some provide a printed handout.

It also helps to compare a player with his own baseline. Some schools and leagues collect baseline information before the season, such as a symptom checklist or a memory and balance test, so a clinician has something personal to compare against after an injury. Baseline testing is one tool among several, and it does not replace a clinical evaluation, but it can make the evaluation more informed. Ask your athletic trainer or league whether such testing is part of the program.

Concussion myths that get in the way

Several widespread ideas make recognition harder:

• "If he did not pass out, it was not a concussion." Most concussions do not involve loss of consciousness.
• "He walked it off, so he is fine." Walking proves little about brain function.
• "It is just a headache." A headache after contact is the most common symptom.
• "Kids bounce back right away." Younger brains are still developing, and children often take longer to recover than adults.
• "A new helmet means we do not have to worry." No helmet eliminates the risk.

A fuller discussion is in our article on concussion myths and facts.

A quick checklist for parents and coaches

Before the season, learn the symptoms and the plan. Programs often use free educational materials from public health agencies such as the Centers for Disease Control and Prevention, whose Heads Up program offers fact sheets for coaches, parents and athletes. Recreational leagues listed in our Play section should be able to show you a written concussion policy. Ask the league who is responsible for removing players, who will be on site at games, and what written clearance is required. High school teams can find programs near them in our high school directory.

The short version

• A concussion is a brain injury caused by a blow or jolt, and most concussions involve no loss of consciousness.
• Watch for signs such as confusion, clumsiness, slow answers, memory problems and mood changes, and ask players how they feel.
• Symptoms include headache, dizziness, nausea, fogginess, light sensitivity, sleep changes and irritability, and they can appear hours later.
• If a concussion is suspected, remove the player from the game and do not allow a return that day.
• Call 911 for danger signs such as worsening headache, repeated vomiting, seizures, unequal pupils or growing confusion.
• A health care professional diagnoses a concussion and decides when a player may return.
• Teams should create a culture where speaking up is rewarded.