A concussion is an invisible injury caused by a rapid back-and-forth movement of the head that causes the brain to hit the walls of the skull.

A concussion can result from a direct blow to the head or from an impact to any other part of the body that transmits an impulsive force to the head.

The main signs and symptoms

Warning signs requiring an immediate medical evaluation at a hospital emergency department (911):

  • Loss or deterioration of consciousness
  • Confusion
  • Repeated vomiting
  • Convulsions
  • Headaches getting worse
  • Significant drowsiness
  • Difficulty walking, speaking, recognizing people or places
  • Double vision
  • High state of agitation, excessive crying
  • Serious balance problems
  • Weakness, tingling or numbness in arms or legs
  • Intense neck pain

Symptoms experienced by the participant or observed by others present and that require a medical evaluation as soon as possible

  • Headaches or pressure in the head
  • Fatigue, drowsiness
  • Difficulty sleeping
  • Nausea
  • Vomiting
  • Dizziness, vertigo
  • Feeling slowed down
  • Concentration problems
  • Memory problems
  • Blurred vision
  • Sensitivity to light
  • Sensitivity to noise
  • Unusually emotional, irritable, sad
  • Nervous, anxious
  • Neck pain
  • Searches for words or repeats them

For the complete list of symptoms, please see the tracking sheet in the Concussion Management Protocol: For Use by Educational Institutions and in the Context of Recreational and Sports Activities.


Most concussion symptoms diminish noticeably within 14 days. If the participant’s state of health does not show obvious signs of improvement after 14 days, or if the symptoms persist beyond one month, contact a family doctor or the specialized resource in your region.

A progressive return to activities prevents complications, respects the participant’s capacity to recover and helps maintain social ties.

The sports context

Compared with other daily life situations, the practice of sports activities is more likely to cause repeated concussions in a short period of time. The victim can also be more vulnerable to a subsequent concussion even after a slighter impact. In such cases, the number of consequences may even increase.