Research into concussion recovery is ongoing, and while there are many theories, there are two key points that doctors and scientists consistently agree on.

First, the cause of the concussion does not affect recovery time. The brain does not distinguish between a concussion caused by a fall, a car crash, or a sports injury. A concussion is a concussion, and the brain will take the time it needs to recover regardless of how the injury occurred.

Second, a person’s history of concussion matters. Research shows that people with previous concussions — particularly those with more severe or longer-lasting symptoms — are more likely to experience longer recovery times after subsequent injuries (Harman, 2013).

Symptoms may fade before the brain fully recovers

A recent American study compared the brains of 50 people diagnosed with a mild concussion to 50 people with no concussion. While many symptoms, such as headaches, resolved within a few weeks, brain scans taken four months later showed ongoing differences in how fluid moved within the brain. This suggests that, even when symptoms improve, the brain itself may not yet have fully healed (Hallock, 2023).

Why do some people take longer to recover?

Dr David Stamatakis from the University of Cambridge has highlighted a key challenge in concussion care:

“At present, we have no clear way of working out which patients will recover quickly and which will take longer.”

This uncertainty can result in some people not receiving adequate support for ongoing symptoms (Stamatakis, 2023).

In a study conducted with the CENTER-TBI project, researchers examined 108 concussion patients and compared them to 76 healthy volunteers. Brain scans revealed that 45% of patients with ongoing symptoms showed abnormalities in the thalamus — a key brain region responsible for relaying information.

Rather than showing obvious structural damage, the thalamus appeared to be over-connected, likely attempting to compensate for injury. As researcher Woodrow explained:

“The thalamus appears to be over-compensating, and this may be at the root of some of the long-lasting symptoms patients experience.”

The study also found that people experiencing emotional symptoms, such as depression, showed increased connectivity between the thalamus and areas of the brain involved in serotonin regulation (Woodrow, 2023).

NHS guidance and the reality of recovery

According to NHS guidance, concussion symptoms can last up to three months, with around 80% of people experiencing post-concussion symptoms during this time. For people over the age of 40, symptoms may persist for six to twelve months.

The NHS advises:

• Resting physically and mentally for the first 48 hours
• Avoiding driving or operating machinery
• Gradually returning to normal activities
• Avoiding stressful situations
• Not returning to work or sport until symptoms have resolved
• Avoiding contact sports for at least three weeks
• Following a gradual return-to-play programme after a minimum of 14 days rest (NHS, 2022)

However, growing scientific evidence suggests that symptom-based timelines alone may be misleading. Symptoms can improve before the brain has fully recovered, meaning a return to sport or activity too soon may increase the risk of prolonged symptoms or further injury.