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Concussion - if in doubt, sit it out

Diagnosis, advice, and treatment of concussions have changed in recent years. On this page, you will get advice based on the latest research.

It can be difficult to determine whether or not someone has experienced a concussion. The rule of thumb is: if in doubt, sit it out.

A few years ago, it was necessary to have been unconscious or suffer memory loss in order to be diagnosed with a concussion. This has changed in accordance with newer research.

Research has also contributed to new advice on the treatment of concussions, and there are new guidelines for when an athlete is ready to return to sport.

How does the injury occur?

A concussion occurs after a blow or an other injury to the head where the head is subjected to rapid acceleration forces that shake the brain. The blow would usually need to be against the head, face or neck, but a concussion can also result from impacts to other parts of the body.

How is the diagnosis made?

A major challenge with concussions is that it's not always possible to make the diagnosis before some time has passed and one can assess the athlete's condition and behaviour in the time after the injury.

A group of experts has further developed a simple diagnostic tool allowing coaches to diagnose and take care of athletes with a suspected concussion. It is the "Concussion Recognition Tool (CRT 5)". There is also a version available to use when children are involved (Child SCAT5). 

One does not have to faint for a concussion to have occurred. However, if the athlete does experience a loss of consciousness it is important to note that there is a certain degree of correlation between the duration the athlete is unconscious and the severity of the injury. Some athletes also experience a period of memory loss. This has been shown to be related to how long the recovery period will be.

Signs, symptoms and indicators

Typical symptoms are headaches, dizziness, nausea, unsteadiness, poor balance, seeing «stars», hearing a ringing noise (tinnitus), and double vision.

Typical signs are poor coordination, loss of consciousness, cramps, slow speech, changes in personality, abnormal emotional outbursts, being easily distracted, nausea/vomiting, glassy eyes, confusion, and reduced performance.

Typical indicators that an athlete has a concussion is that they have difficulty orientating themselves in the situation they're in. For example, if an injury occurs during a handball match, it might be that the athlete can't remember which period it is, who they're playing against, the score, what just happened and where they are. They might not even recognise that they are confused. Loss of consciousness can also be an indicator.

Precautionary measures

An athlete who has suffered a concussion should be under constant supervision for the first 24 hours following the injury, and assessed by a doctor before recommencing training. As a rule of thumb, an athlete who has suffered a blow to the head should not return to sport if they are experiencing one or more symptoms of a concussion.

It is important to follow this advice: If in doubt, sit it out.


The athlete should stop all activity if a concussion cannot be ruled out. Following this, they should rest under supervision for at least 24 hours. As part of the monitoring process, the athlete should be woken up a couple of times during the night.

If the signs or symptoms worsen or persist, the athlete should be examined at a hospital as soon as possible.

Anyone who has been unconscious or doesn't remember the period leading up to the injury should have a medical imaging examination of their brain (using CT, MRI, etc.). This is done in order to rule out serious injury.

Symptoms will usually subside within a few days, though it can take some people weeks or even months to be completely recovered. Between 5 and 10% will continue to experience some form of discomfort more than 3 months after the injury. This can include headaches, dizziness, difficulty concentrating, and mood swings. In most cases, these symptoms will diminish over time.

Return to sport

The guidelines for when an athlete can return to training and sporting activities is based on a step-by-step process. In this process, the athlete progresses from one level of activity to the next, once they are symptom free at their current level:

  • No activity or training, complete rest. When symptom free, go to the next level
  • Light aerobic exercise such as walking or using a stationary bike
  • Sport specific aerobic exercise (e.g. running for a football player, ice skating for an ice hockey player)
  • Non-contact sport specific exercises
  • Full training without restrictions
  • Return to sport

If symptoms come back once an athlete has gone up a level, they should return to the previous level and wait 24 hours before trying to go up again.

Athletes who have had a concussion and completely recovered are no more susceptible to a new concussion than anyone else. have new concussion than anyone else. However, repeated concussions can be linked to the amount of risk an athlete is willing to take while performing in their sport (e.g. speed for a downhill skier, heading the ball for a football player).