How long does concussion last? Weeks for most, longer for some

If you have had a knock to the head and still feel off days or weeks later, the first question is usually how long this is meant to last. For most people the honest answer is days to a few weeks. For a smaller group it is longer, and that group is bigger than many people expect.

This guide covers what UK guidance says about recovery time, what post-concussion syndrome means, what can slow things down and when to get help. If your injury happened in the last day or two and any of the warning signs below apply, stop reading and get medical help first.

How long does concussion usually last?

The NHS says you might have symptoms for up to 2 weeks after a minor head injury, and describes concussion as a temporary brain injury that can last a few weeks. Headway, the UK brain injury charity, says that for most people concussion symptoms resolve in a few days or weeks.

Symptoms do not always start straight away. NHS inform notes that it can take up to 48 hours for concussion symptoms to appear, so feeling fine on the evening of an injury does not rule it out.

Typical early symptoms include:

• headache
• dizziness or feeling sick
• feeling stunned, dazed or slow to answer questions
• blurred vision or "seeing stars"
• irritability or acting out of character
• trouble remembering what happened around the injury

NICE's written advice for adults leaving hospital lists a mild headache, dizziness, irritability, problems concentrating, problems with memory, tiredness, lack of appetite and problems sleeping as symptoms that should disappear within 2 weeks.

What counts as post-concussion syndrome?

When symptoms carry on for longer than expected, doctors often use the term post-concussion syndrome, or persistent post-concussion symptoms. You will also see it shortened to PCS. NHS inform uses the term for symptoms lasting more than 28 days, and advises contacting your GP practice at that point.

The symptoms are familiar ones that simply have not settled: headaches, dizziness, poor concentration, memory problems, extreme tiredness and intolerance of light and noise. Headway notes they can lead to anxiety and depression, which can make the whole picture harder to shift.

NICE guidance on head injury states that post-concussion syndrome is seen in all severities of head injury and is under-recognised in mild head injuries. In other words, a "minor" knock can still leave a real and lasting problem.

How common is it?

Estimates vary with how PCS is defined and who is studied. Headway summarises a systematic review and meta-analysis of adults who went to an emergency department or trauma centre with a mild traumatic brain injury. Three to six months later, around 31% met a lenient definition of PCS and around 18% met a stricter one. The figure could be closer to 1 in 6 once people lost to follow-up were accounted for.

Those numbers come from people who attended hospital, who may have had more significant injuries than someone who never sought care. They are a guide, not a prediction for any individual.

What can make concussion recovery take longer?

NHS inform lists several factors linked with a slower recovery:

• being a child or young person
• a significant history of previous concussion
• being a female athlete
• ADHD or a mental health condition

Going back to contact sport too early is another. NHS advice is to avoid contact sports for at least 3 weeks, and NHS inform recommends a graduated return that takes a minimum of 21 days before a full return to normal life and sport. A second knock before the brain has recovered can make things worse, and in rare cases much worse.

Headway also makes a point that is easy to overlook: the fear of having a brain injury can itself be distressing and can delay recovery. Knowing that most people do get better is part of looking after yourself.

How long does it take for a concussion to heal, and what helps?

There is no single healing date. Most guidance describes a short period of rest, followed by a gradual return to normal life that is guided by symptoms.

• The first few days. NICE's discharge advice is to rest for 2 to 3 days, then gradually return to work and normal activities. If symptoms get worse, go back to a level of activity that was manageable. NHS inform describes 24 to 48 hours of relative rest, and says light activity has been shown to be more beneficial than complete rest.
• Screens and concentration. NHS inform suggests keeping screen time to a minimum in the first 24 to 48 hours, then building it back up.
• Alcohol and medicines. The NHS advises no alcohol until you feel better, and no sleeping pills unless a doctor advises them.
• Driving. Do not drive until you feel fully recovered. After a serious head injury, GOV.UK guidance says you must tell the DVLA, and your doctor can advise if you are unsure.
• Work. Returning in stages, with breaks and a lighter load at first, is usually easier than going straight back to a full week.

When should you see a doctor about lingering concussion symptoms?

Call 999 if, after a head injury, someone:

• has been knocked out and has not woken up
• cannot stay awake or keep their eyes open
• has a fit (seizure)
• has new numbness or weakness in any part of their body
• has problems with walking, balance, understanding, speaking or writing
• has clear fluid coming from their ears or nose, or is bleeding from their ears
• has problems with their vision or hearing
• has changed behaviour, such as being more irritable or distracted

That list comes from the NHS and is not complete. If you are unsure, contact NHS 111.

See a GP if symptoms last more than 2 weeks, or if you are not sure whether it is safe to drive or return to work, school or sport. It is also worth knowing that NICE reminds doctors that a head injury of any severity can affect the pituitary gland, and that this can show up weeks or months later. Ongoing tiredness can have more than one explanation, which is another reason to get checked rather than assuming it will pass.

Where does hyperbaric oxygen research fit?

Hyperbaric oxygen therapy (HBOT) is not a treatment for a new head injury. A recent injury needs NHS assessment. The research question is narrower: whether HBOT changes symptoms that have already lasted many months.

The most relevant recent study is a 2025 double-blind, sham-controlled trial in Scientific Reports. It included adults aged 18 to 70 whose brain injury had happened between 6 months and 10 years earlier. Participants had 40 sessions at 1.5 ATA, the same pressure our chamber uses, or 40 sham sessions, over 12 weeks. Across the 47 people analysed, symptom scores improved by 10.6 points in the HBOT group and 3.6 points in the sham group, a difference of 7.0 points.

The limits matter as much as the result. The trial recruited about a third of its intended sample and was stopped when funding ran out and recruitment slowed. Both groups improved. An earlier US military trial of 72 service members, also using 40 sessions at 1.5 ATA, found no benefit over sham, and its authors suggested placebo effects could explain the improvement seen in both chamber groups.

So the evidence is encouraging in places and contradictory in others. It is not a promise that any individual will improve. Our head injury evidence page sets out the numbers in more detail, and who HBOT is not suitable for covers the safety questions to ask first.

The practical summary

Most concussion symptoms settle within a couple of weeks. If yours have not, that is a reason to see your GP, not a reason to push through alone. If symptoms have lasted months, your GP has looked at other causes and you want to explore the research option, you can read what HBOT is and, when you are ready, see available times. No referral needed. Medical consultation included.