What Playing Professional Football In The NFL Can Do To Your Brain

In 2019, a reported 224 NFL players suffered concussions — that's 10 more cases than the year prior, as reported via Vox. Following a blow to the head, players may experience concussion symptoms such as disorientation, headaches, sensitivity to noise or light, headaches, confusion, and more. Such symptoms may be short-lived or long-lasting, but they all result from the brain having been jostled around in the skull.

Researchers from a 2017 study published in JAMA Network set out to discover the ways in which playing professional football could potentially impact brain health in the long run. Using over 200 donated brain samples from deceased American football players, the study team found that football athletes were more susceptible to long-term neurodegenerative diseases. Out of 202 brain samples, chronic traumatic encephalopathy (CTE) was detected in 177 of them. While high school football players also stood at an increased risk for neurological damage, the greatest levels of severity were observed in former college players, semi-professional players, and professional players.

For the average person, CTE is considered a rare condition, according to the Mayo Clinic. Characterized by cognitive, mood, behavioral, and motor changes as a result of continual head trauma, athletes who play contact sports are among those more prone to the condition. Exactly how many head injuries can lead to CTE, however, is still unknown. 

In the 2017 study, results of telephone interviews with the deceased player's families revealed that regardless of the severity of brain damage observed in brain imaging scans, all players diagnosed with the condition displayed CTE symptoms ranging from depression to impulsivity, episodic memory loss, explosive rages, and more (via Science). Additionally, 96% of diagnosed players reportedly experienced worsening symptoms over time.

Such findings support earlier studies demonstrating links between football players and neurodegenerative disease. A 2012 study published in Neurology found evidence that retired National Football League players were four times more likely to die from Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS). "Multiple research studies have raised concerns about the longer-term health effects of recurring concussions," said Dr. John Howard, Director of the National Institute for Occupational Safety and Health (NIOSH), the agency that published the 2012 study, in a statement via the U.S. Centers for Disease Control and Prevention (CDC).

With more and more research linking football to head injuries, the NFL has made efforts to better protect players in recent years. Such efforts include banning helmet-to-helmet hits (Vox), as well as prohibiting the use of helmet models that underperformed in laboratory safety testing in 2018 (per Yahoo! News).

JAMA Network's 2017 study on chronic traumatic encephalopathy (CTE) found that the neurodegenerative brain disease affected 99% of NFL players whose brain tissues were analyzed. The researchers identified CTE in the brains of NFL players through clusters of the tau protein in the neurons in addition to irregular twisted tau fibers, per Science. Both irregularities were found in the lower layer of the cortex's folds, with more extreme cases of CTE containing abnormalities in deeper brain structures like the amygdala. Notably, while other neurodegenerative diseases like Alzheimer's may have irregular tau protein clusters, the clusters in CTE cases are in locations that are considered unique.

New York University Grossman School of Medicine notes that the repetitive brain trauma from sports like football affects the chemical altering of tau proteins. Tau proteins in CTE begin to tangle and destabilize, which negatively impacts its capacity to carry molecules and nutrients to brain cells, which can eventually result in the death of brain cells. This can be seen in the brain as small black dots. This degradation of the brain can lead to changes in behavior, cognition, and mood for the individual, often for the worse.

MedicineNet reports that there are four main stages of chronic traumatic encephalopathy (CTE). During the first stage, the person may experience headaches and issues with holding attention and focusing. The second stage of CTE can bring on fits of depression, loss of short-term memory, and even irregular moods marked by explosive episodes. In the third stage, various impairments to memory can impact one's ability to think about the future, stay organized, and even work on two or more things at once. In the fourth and final stage of CTE, the individual may experience severe symptoms of aggression and violence, memory loss, substance abuse disorder, changes to personality, and even thoughts about suicide. A true crime story about a professional NFL player who was found to have CTE best places these symptoms and stages into context.

According to a 2020 study published in the Journal of the American Academy of Psychiatry and the Law, star football player for the NFL's New England Patriots — Aaron Hernandez — was convicted of first-degree murder and took his own life in prison. Upon an autopsy, it was discovered that Hernandez had an advanced case of CTE.

Hernandez's story is one of many others in the NFL community where CTE has been discovered after a player has committed a violent act before taking their own life (per The Guardian).