Lifelong consequences of head injuries in football players

Sarah Boothman, Ph.D.
November 2026
(6 Minutes)

I was raised in a football family. Every Sunday from September to January, our house would be filled with the sounds of the game. I joined the family fantasy league when I was 14, and I’ve participated in it every year since. To me, football will always be synonymous with fall, family, and friends. However, as a scientist, it’s hard to ignore the data that’s been revealed over the last decade detailing how harmful the sport can be for players’ neurological (brain) health. While we cheer on the sidelines, what’s happening under the helmet?

As a contact sport, football harbors a high risk of injury. In fact, approximately 300,000 football-related concussions occur every year in the US. A concussion, also referred to as a traumatic brain injury (TBI), occurs when someone experiences a hard blow to the head and brain tissue swells. Because football players have a higher chance of experiencing a concussion (or repeated concussions), it is important to understand the long-term impacts of these injuries on their neurological health. Research on this topic began as early as the 1920s, when physicians began observing odd psychiatric symptoms and cognitive decline in boxers (“punch drunk” syndrome). As studies advanced, doctors noticed differences in the brains of these athletes after they died. These findings expanded to football players in 2006 when pathologists at the University of Pittsburgh reported dramatic changes in the brain of a deceased NFL player and suggested that they may be linked to the repeated TBIs he sustained during his career. A few years later, researchers at Boston University School of Medicine compiled a comprehensive review of these brain changes in professional athletes, and they found that football players developed symptoms faster and died sooner than other athletes on average. These findings elevated concern over how repeated TBI affects football players’ long-term neurological health and led to numerous research studies around the topic. This all came to a head in 2013, when thousands of former players and their families sued the NFL for concealing the dangers of concussions and not giving players proper treatment before putting them back on the field. The lawsuit ended in a $765 million settlement, and the NFL poured even more money into initiatives to prevent head injuries to its players.

The particular disease pattern found in these studies is known as chronic traumatic encephalopathy (CTE). The two main criteria for CTE diagnosis are brain atrophy (shrinking/shriveling) in certain areas and the presence of protein clumps called neurofibrillary tangles (NFTs) in the brain. The symptoms associated with CTE, collectively called traumatic encephalopathy syndrome (TES), include memory loss, executive dysfunction (the inability to plan, focus, manage time, etc.), anger issues, and emotional instability. In recent years, CTE/TES has been found to be extremely common among football players. In 2017, researchers studied the brains of deceased football players and found that 87% were positive for CTE. Additionally, a study released this year found that among the brains donated from NFL players who died between 2016 and 2021, one in four were positive for CTE. Professional football players who are experiencing TES are also more likely to struggle with depression and anxiety, which likely contributes to the rising suicide rates of NFL players. Findings such as these have made CTE a major concern among football players and have highlighted the need for more research and better practices on the field.

One major roadblock to researching and preventing CTE is the nature of the disease. There is currently no way to diagnose someone with CTE until after they die and an autopsy is performed. Unlike other neurological diseases such as Alzheimer’s, there are no known biomarkers associated with CTE that doctors can test for while patients are alive, and current brain imaging techniques do not have the resolution necessary to diagnose CTE. Additionally, many TES symptoms can be caused by other conditions, so doctors first must rule out other diseases when assessing a patient for CTE/TES and then weigh the risk factors that the patient has for developing CTE. The number one risk factor for CTE is repeated head injury (RHI), and there is little evidence that CTE can form without RHI, making professional football players extremely vulnerable to the disease.

In response to all of these findings and the legal action taken by players and their families, the NFL has implemented updated equipment, regulations, and procedures in all of its games. Each player now has access to better helmets to reduce the chance of TBI, and these helmets are specialized for each position on the field. “Guardian” helmets, which feature foam padding on the outside, are required for all practices and players can choose whether to wear them during games. Additionally, new rules were set in place on the field to reduce the amount of helmet contact and head strikes players experience during games. When a player does experience such a hit, improved concussion protocols ensure that they do not get back on the field until they are cleared by a concussion expert on the sidelines. Since implementing these changes, the NFL has seen significantly lower concussion rates, with the 2024 season being a record-low. Despite this, there is still room for improvement, and the NFL continues to fund research for innovative ways to keep its players safe.

While the NFL and the medical community pour time, resources, and energy into this issue, I am left wondering what our response as fans should be. Approximately 20 million people in the U.S. tune in to watch their favorite football teams every weekend, which generates massive amounts of revenue for the NFL and its players. While we might just be enjoying a great American pastime with our friends and family, we are also passively supporting the harm that these men are experiencing. It is ultimately the players’ decisions to assume the risk of CTE in exchange for the financial compensation and notoriety they receive, but we also have a choice in how we support the NFL, how we stay informed on the latest research, and how we talk about these issues with the next generation of football players and spectators. Even while researching for this article, I have changed the way that I perceive the players who choose to wear the funny-looking (yet more protective) helmets during games. Hopefully, combined efforts from researchers, administrators, and players will continue to change the way football looks, so we can all enjoy the sport we love while reducing harm.