Fact Sheet: Concussions

Find out what you need to know about concussions.

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OVERVIEW: A concussion is the most minor form of brain injury. Symptoms of a concussion may not start right away; they make start days or weeks after the injury. They are diagnosed using a neurologic exam and imaging tests. Most people recovery fully after a concussion, but it can take time. Physical and cognitive rest are very important after a concussion because they helps the brain to heal.

LONG TERM RISKS: Most kids, if their concussions are managed properly and they don’t go back into risky situations until they’re recovered, will be fine. The most common long-term problem is delayed or incomplete recovery.  This can be seen after multiple concussions, or recurrent concussions, occurring prior to the complete recover from previous concussion.  Some rare situations get a lot of media attention, like second impact syndrome.  This happens when a person who isn’t completely recovered is struck again, and they can get massive brain swelling, leading to a vegetative state or death.

People who have already sustained a concussion are at greater risk for subsequent concussions. The effects are likely cumulative, so each causes more severe symptoms and longer recovery time. Nobody knows what the magic number is when you start to see a long-term effect.

STATISTICS: It is estimated as many as 3.8 million concussions occur in the US per year during competitive sports and recreational activities; however, as many as 50% of concussions may go unreported.

The top 10 sports-related head-injury categories that resulted in emergency room visits in 2009 among children ages 14 and younger:

  • Biking: 40,272
  • Football: 21,878
  • Baseball and Softball: 18,246
  • Basketball: 14,952
  • Skateboards/Scooters: 14,783
  • Water Sports: 12,843
  • Soccer: 8,392
  • Powered Recreational Vehicles: 6,818
  • Winter Sports: 6,750
  • Trampolines: 5,025

According to the National Center for Catastrophic Sport Injury Research (NCCSIR), while football is associated with the greatest number of catastrophic injuries, the injury rate per 100,000 participants is higher in both gymnastics and ice hockey. The total number is higher simply because more people participate in football than gymnastics or ice hockey. Catastrophic injury is defined as fatal, non-fatal (permanent severe functional disability), or serious injury (no permanent functional disability but severe injury).

NCCSIR also notes that there have been dramatic reductions in the number of football fatalities and non-fatal catastrophic injuries since 1976, when a rule change was introduced that prohibited initial contact with the head in blocking and tackling. Helmet standards, improved medical care of injured athletes, and improved coaching techniques of fundamental blocking and tackling skills have also contributed to the decrease.  

EMERGING RESEARCH: Researchers know that immediately after a concussion, the brain is especially vulnerable to having a second, more serious injury.  Studies have found that the risk for a second injury is greatest in the 10 days following an initial concussion, but it is not entirely clear why.  A UCLA study found that in rats, a single mild injury reduces the brain’s use of glucose as fuel.  A second mild injury 24 hours later leads to an even steeper drop in glucose use and memory problems that last longer. But when the brain has several days to recover, and the use of glucose returns to normal, a second mild brain injury seems to be no worse than the first.

Kids' repeat concussions may mean longer recovery Pediatrics, June 2013

  • Children and young adults (age 11 to 22) who suffered second concussion in the last year took an average of 35 days to recover, rather than typically prescribed 2 weeks
  • Recovery time for participants who had never had a concussion was about 12 days

Concussion damage looks much like early Alzheimer’s, Radiology, June 2013

  • Concussion can lead to damage in white matter of brain that resembles abnormalities found in people in early stages of Alzheimer’s
  • Researchers reviewed past brain scans of 64 people who had suffered a concussion
  • Compared scans to symptoms reported by patients in post-concussion questionnaire, focusing on symptoms shared with Alzheimer’s patients, including memory problems, disturbances in sleep cycles, and hearing problems
  • Results show significant correlation between high concussion symptom scores and reduced water movement in parts of the brain’s white matter related to auditory processing and sleep-wake disturbances
  • Study has drawn criticism for methods used (reliance on existing brain scans and symptom charts), inclusion of young patients (white matter is not fully development until adulthood), and the use of sleep disturbance as a comparable symptom between Alzheimer’s and concussion

Brain may recover from concussion by compensating, Journal of the International Neuropsychological Society, August 2013

  • fMRI used to study recovery of 12 high school football players with concussion compared to 12 uninjured teammates 
  • Underwent brain scans 13 hours and 7 weeks after injury
  • At 13 hours, concussed athletes had decreased reaction time and reduced mental abilities. 
  • Scans revealed decreased activity in certain areas of right hemisphere, suggesting reduced mental abilities may be related to underactivation of attentional brain circuits
  • At 7 weeks, concussed players showed improvement in mental abilities and reaction, and scans revealed that concussed players had more activation in brain attentional circuits 
  • Hyperactivation may represent a compensatory brain response that mediates recovery


  • Concussion risk is greater in individuals who have already had a concussion
  • Primary prevention of some injuries may be possible with enforcement of the rules and fair play.
  • Certain sports, positions, and individual playing styles have a greater risk of concussion. Significant percentage of concussions can be attributed to “illegal play” (25.3% in high school athletes) and are often associated with player-player contact.
  • In football, linebackers and running backs are most concussed players
  • Helmets, both hard (football, lacrosse, and hockey), and soft (soccer, rugby), are best suited to prevent impact injuries (fracture, bleeding, laceration, etc) but have not been shown to reduce the incidence and severity of concussions.
  • Current research in helmet technology shows promising results suggesting a 10-20% lower risk of concussion with newer helmets. There are ongoing efforts to continue research and development of this type of technology.
  • Neck strengthening may limit transmitted forces to the head and dampen impact to the brain.
  • From a theoretical standpoint, increased strength in the head-neck segment could decrease the acceleration forces seen by the head when it is struck. This hasn’t been yet validated by any studies.
  • Secondary prevention may be possible by appropriate return-to-play management, in a step-wise progression of allowable activity. 

OMEGA 3s: Omega 3s serve as both an essential cellular component in the brain and, once converted, anti-inflammatory prostaglandins.  By countering inflammation, the adequate consumption of omega-3s can help to decrease the production of inflammatory prostaglandins and potentially decrease brain trauma-related inflammation.


Playing sports has a range of physical, emotional, and interpersonal benefits:

  • Better vision. Children who spend time outdoors playing, especially organized sports, are less likely to develop vision problems.
  • Healthy weight. Obesity is increasing in children, but data show that kids who are more active, especially after school, are more likely to be of normal weight.
  • Motor skills development. Sports participation helps with coordination and learning new skills.
  • Social skills development. Playing on a team means learning to work with others and support them.
  • Self-confidence. Success as a team member and an athlete builds confidence.
  • Sportsmanship. Learning the rules of the game, respect for coaches and referees, and how to stay positive even when losing are all valuable life lessons.
Have questions about concussions? Read this FAQ.