Head & neck

Concussion

Also called: mild traumatic brain injury, mild TBI, head knock, brain injury. Clinical name: Concussion (mild traumatic brain injury).

A concussion is a mild brain injury from a knock to the head. Most adults feel back to normal within about 2 weeks, and many within 7–10 days — though children and teenagers often take longer.

What it actually is

A concussion is a mild traumatic brain injury caused by a knock, bump or jolt to the head — or even a hard hit to the body that jolts the head sharply. The force makes the brain move quickly inside the skull, which briefly disrupts how it works. Nothing is usually broken or bleeding; it’s a temporary change in brain function rather than visible structural damage, which is why it’s called “mild” — though it’s still a brain injury and worth taking seriously.

It doesn’t present the same way in everyone. Common signs include a headache, feeling dizzy or off-balance, nausea, and a foggy, slowed-down feeling where it’s hard to concentrate or remember things. Sensitivity to light and noise, tiredness, disturbed sleep and feeling more emotional than usual are all part of the picture too. Some of these can appear straight away, while others build over the first day or two.

One common misunderstanding is that a concussion means being knocked out — it doesn’t. Most people with a concussion never lose consciousness. This page is general information, not a diagnosis: if you or someone else has taken a knock to the head and feels unwell, the safest step is to have it assessed, and to watch closely for any of the emergency warning signs above.

How bad is it?

You may have seen concussion sorted into grade 1, 2 or 3. Those older numbered grading systems are no longer generally recommended, because they didn't predict recovery well. Instead, a concussion is now described by which symptoms you have and how long they last. Most adults feel back to normal within around two weeks, and many within 7–10 days (NHS; AAOS) — but children and teenagers often take longer, and no two recoveries look quite the same. Because this is a brain injury, the safest reason to take it seriously early is that a second knock before the first has settled can set recovery back considerably.

How long will it take?

Recovery moves in phases. This is the typical shape of it — yours may run faster or slower, and the numbers below are general ranges, not a forecast for your specific injury.

First 24–48 hours
Relative rest. Take it easy physically and mentally — no contact sport, no driving if you feel off, and it helps to have an adult stay with you for the first day. This is the window red-flag symptoms are most likely to show, so the priority is watching for anything that's getting worse rather than pushing through.
Days 2–7
Gentle, gradual activity. Complete rest in a dark room is no longer advised. Once you're a couple of days in, light activity that doesn't clearly worsen your symptoms — a short walk, easy daily tasks — is generally encouraged, backing off if headache, dizziness or fogginess flare (AAOS).
Week 1–2
Return to school or work in steps. Build back screen time, reading and concentration gradually rather than all at once, and stop short of the point where symptoms spike. Most adults are recovering well through this window (NHS).
From ~3 weeks (return to play)
Staged return to sport. Contact sport should be avoided for at least 3 weeks, and rougher play a little longer for children (NHS). Return to play is done in stages — light exercise, then sport-specific drills, then full training — moving up only if symptom-free, ideally with clinician sign-off.
Beyond a few weeks
The longer tail. A minority have symptoms that linger past the usual couple of weeks. If you're not steadily improving, or symptoms persist, that's the point to be reassessed by a clinician rather than waiting it out alone.

When to get it looked at

Most cases settle with time and sensible loading. Get it assessed by a professional if any of these apply — they can point to something that needs hands-on care:

  • Being knocked out and not waking up, or not being able to stay awake / keep your eyes open — call 999
  • A fit or seizure in someone who doesn't normally have them — call 999
  • Clear fluid coming from the ears or nose, or bleeding from an ear — call 999
  • New numbness or weakness in any part of the body, or problems walking, speaking, balancing or understanding — call 999
  • Repeated vomiting, or a headache that keeps getting worse and won't go away — get urgent medical help
  • Growing confusion, unusual drowsiness, or behaviour that seems increasingly out of character — get urgent medical help

This is a list of warning signs, not a diagnosis. If you are worried, or the pain is severe, see a GP, physiotherapist or urgent care.

What to track while you recover

Concussion recovery is measured by symptoms, so the most useful thing you can do is write them down each day. A simple record shows whether you're trending better or worse — which is exactly what a clinician needs, and hard to judge from memory when you're feeling foggy.

  • An overall symptom score, 0–10, for how you feel each day (the single most telling number for concussion)
  • Sleep: how well you slept and whether you feel rested, since sleep disturbance is common early on
  • Screen tolerance: how long on a phone or computer before symptoms build
  • Headache: how bad, how often, and whether it's easing or worsening day to day
  • Anything that clearly triggered symptoms — bright light, noise, exercise, concentration, reading

This is exactly what InjuryLog does.

Log each of these in seconds, watch the trend build day by day, and keep every scan and receipt tied to this one injury. Free to start.

Join the waitlist

What to tell your physio

Whether you see a GP, an A&E clinician or a physiotherapist, the appointment goes faster when you can describe how things have changed since the injury. Bring the pattern over days, not just how you feel in that moment.

  • Exactly how the injury happened, and whether you were knocked out or can't remember the event
  • Which symptoms started, when they appeared, and whether they're improving, static or getting worse
  • What reliably triggers symptoms now — screens, exercise, light, noise, concentration
  • How sleep, mood and thinking (memory, focus) have changed since the knock
  • Any previous concussions, and how long those took to settle

Walk in with the whole picture.

InjuryLog turns your daily logs into a clean Physio Visit Pack, a one-page summary your physio can actually read, so the first appointment starts with facts, not guesswork.

Get early access

The questions people actually ask

How long does a concussion last?

For most adults, symptoms settle within around two weeks, and many people feel better within 7 to 10 days. Because it's a brain injury measured by symptoms, there's no fixed number — some recover faster, and children and teenagers commonly take longer. The best guide is whether your symptoms are steadily trending down. If you're not improving after a couple of weeks, or symptoms are getting worse, that's a reason to be reassessed by a clinician.

Will a concussion show up on an MRI?

Usually not. Concussion is a change in how the brain is working rather than visible structural damage, so standard scans like MRI or CT are typically normal. Scans aren't used to diagnose concussion itself — a clinician assesses it from what happened and your symptoms. Imaging is generally reserved for ruling out a more serious injury, such as bleeding, when certain warning signs are present.

Can I sleep after a concussion?

For most people, yes — the old advice to keep someone awake all night is outdated. Sleep is part of how the brain recovers. What does help early on is having a responsible adult nearby for the first 24 hours who can check on you and get help if you become very hard to wake, keep vomiting, or seem increasingly confused. If you're ever unsure or the person seems to be deteriorating, treat that as an emergency.

Will a concussion heal on its own?

In the large majority of cases it does, with time and sensible pacing rather than any specific treatment. Most adults recover within about two weeks. 'Healing on its own' still means respecting it — easing back into activity gradually and avoiding a second knock while you recover, since another head injury before the first has settled can prolong things considerably. Seek review if you're not improving as expected.

How do I know if my concussion is getting worse?

Day-to-day symptoms can swing, so judge the trend over a few days rather than a single bad hour. The signs that mean get help urgently are different from normal recovery: repeated vomiting, a headache that keeps worsening, new weakness or numbness, a seizure, growing confusion, being very difficult to wake, or clear fluid from the ears or nose. Any of those warrants emergency care. A daily symptom record makes a genuine downward trend much easier to spot.

Can you have a concussion without a headache?

Yes. Headache is common but not universal — a concussion can show up mainly as dizziness, nausea, feeling foggy or slowed down, sensitivity to light or noise, or just feeling 'not right' after a knock. You also don't have to have been knocked out to have one. Because the signs vary so much, any notable symptoms after a blow to the head are worth taking seriously and, if in doubt, getting checked.

Can concussion symptoms be delayed?

They can. Some symptoms are obvious straight away, but others — headache, tiredness, difficulty concentrating, mood changes or poor sleep — can appear or worsen over the hours and first day or two after the injury. That's part of why it's advised to keep an eye on someone for at least the first 24 hours after a head knock, and why new or worsening symptoms should prompt a fresh look rather than being brushed off.

Why does a concussion make you feel sick?

Nausea and sometimes vomiting are common after a concussion, linked to the way the knock temporarily disrupts brain function and the balance system. A single episode of feeling sick can be part of the picture. Repeated vomiting is different — it's one of the warning signs that needs urgent medical attention, because it can point to a more serious head injury. If someone is being sick more than once, get medical help.

Is a concussion the same as a traumatic brain injury?

A concussion is a form of traumatic brain injury — specifically a mild one, which is why clinicians call it a mild traumatic brain injury (mild TBI). 'Mild' describes how it's classified, not how much it matters: it's still a brain injury and deserves proper rest and recovery. The label 'mild' mainly distinguishes it from moderate and severe brain injuries, which involve more serious, lasting damage.

How this article was produced
Written & edited by the InjuryLog team
Every clinical statement here is referenced to the sources listed below (NHS, NHS, AAOS OrthoInfo). This is general educational information, not medical advice, and has not been individually reviewed by a clinician. Last updated 2026-07-13.

Sources

  1. Head injury and concussion — NHS
  2. Head injury and concussion — NHS
  3. Sports Concussion — AAOS OrthoInfo

Educational recovery information only. Not a diagnosis and not a substitute for professional care. Recovery ranges are typical figures from the sources above, not a prediction for your injury.