January 6, 2023
Discussions about the dangers of football have surfaced again after Buffalo Bills safety Damar Hamlin suffered a cardiac arrest during Monday’s night game against the Cincinnati Bengals.
But is football actually the riskiest sport? “Yes and no,” says Daniel Daneshvar, assistant professor at Harvard Medical School and brain injury medicine physician at Mass General Brigham.
“When you’re talking about the most dangerous sports, it really comes down to the kind of injury. Most sports have some level of risk, but football,” he says, “is among those with injuries that often cause permanent damage — especially when it comes to the brain.”
And head injuries are common in the game. In addition to the 187 concussions officially acknowledged by the National Football League (NFL) in the 2021 preseason and regular season, there were likely thousands of subconcussive head impacts. Subconcussive head impacts can also cause problems and have been associated with the degenerative brain disease known as chronic traumatic encephalopathy, or CTE. Just a few months back, Miami Dolphins quarterback Tua Tagovailoa was taken off the field in a stretcher for head and neck injuries. (He’s suffered three concussions this season.)
Grid spoke to Daneshvar about the risks associated with football, other sports high in head injuries that don’t get a lot of attention and how sport organizations can help prevent injuries moving forward (and if they seem to want to). The interview has been edited for length and clarity.
Grid: Let’s start with football because that gets the most attention. Is it truly the most dangerous sport with the most injuries, or is it just the sport with the most severe injuries because it so often affects the brain?
Daniel Daneshvar: It’s important to determine exactly what you’re talking about when we’re asking about whether football is the most dangerous sport in terms of injuries. There are injuries to the brain, there are injuries to the body and different sports have different risks associated with each of those types of injuries.
When we’re talking about neurologic injuries, or brain injuries, football is certainly one of the higher-risk activities. And that’s in part for two reasons. There are a lot of repetitive head impacts and risk for traumatic brain injury in football, and many more people play football at a lot more levels than really any other sport in the United States.
G: What are the short and long-term risks of brain injuries? What about other types of injuries associated with football?
DD: Brain injuries, including concussions, can have both short-term and long-term effects on an athlete’s life and life trajectory. But on top of that, there are also well-established and well-understood risks of orthopedic injuries. A recent study that came out by colleagues of mine at Harvard found that individuals who play football have, throughout their life and including in their 20s, about a three times higher risk of arthritis. That same study found that professional football players had twice as high a risk of having hypertension in their 20s compared to the general population.
G: Some youth football leagues and pro leagues are trying to protect against brain injuries with better helmets. Are they at all effective or just a Band-Aid on the problem?
DD: In lab studies, the best helmets might attenuate the force associated with a head impact by something like 10 percent. And when you’re talking about a head impact that’s 60 or 70 g’s of force, that might decrease the head impact by five or eight g’s. But that amount of force difference is not enough to substantively decrease the risk or severity of concussions that an athlete might experience. I think people want helmets and equipment to be the answer because that would mean that there doesn’t need to be any substantive changes to how the game is practiced or how the game is played, but the technology to date doesn’t really show significant benefit.
It’s the total amount of exposure to these repeated brain injuries that put you at risk for problems later in life. What we could do, then, is decrease that total lifetime burden of head impact.
One way is to limit the total duration of head impact exposure that an athlete experiences. For example, in a study we published two years ago, we found that every additional year of playing football was associated with a 30 percent increased risk of CTE (chronic traumatic encephalopathy), a neurodegenerative disease that can lead to dementia.
The other thing you can do to decrease the total amount of head impacts that athlete experiences is by changing how they practice and how they play. Almost two-thirds of these head impacts occur in practices, so it’s hard to necessarily justify all the types of drills that lead to these head impacts that athletes are experiencing.
G: What happens if a concussion or brain injury goes untreated?
DD: It puts people at risk for subsequent and worse brain injuries. A concussion is an injury to the brain that results in a metabolic imbalance between what the brain needs to function and what the brain can receive. During the time period immediately after the concussion, there’s what we call a window of vulnerability, where the brain tissue is still recovering, and a subsequent hit to the head during that period can prolong or worsen the injury itself. When an athlete is not properly being evaluated and treated for concussion, they can be at higher risk for persistent post-concussion syndrome, which is when the symptoms of the concussion take months or even years to resolve.
One of the other things that’s often overlooked when it comes to untreated concussions is that you’re not just at higher risk for injuries to your brain, but you’re also at higher risk for injuries to the rest of your body. For example, an athlete with an untreated concussion is at about three times higher risk of an orthopedic injury. That’s because the brain isn’t functioning the way it should, so their reaction time is slower and their balance and proprioception are off.
G: What should we know about Chronic Traumatic Encephalopathy (CTE)?
DD: When athletes — or anyone — are getting hit in the head repeatedly, there can be a buildup of a toxic protein in their brain that can lead to neuronal cell death. When that process starts, it can lead to a neurodegenerative disease that progresses as an athlete continues. So, the problems associated with this toxic protein don’t really show up for decades later. When we talk about athletes who have memory problems, attention problems, concentration problems later in life and pass away with dementia, we’re finding that the underlying process in their brain is CTE, which is a neurodegenerative disease process. When we find things like NFL players are at a 10 times higher risk of dying from dementia than other athletes, the disease process that is thought to be responsible is CTE.
G: Is there anything misleading that the NFL or other sports organizations say to protect themselves?
DD: The NFL, at least, is letting athletes know that there are risks associated with these head impacts. There are posters up in the locker rooms. We might discuss the extent to which the NFL is appropriately conveying these risks, but they are at least acknowledging that there is a risk. This puts them in contrast to other sports organizations, including the NCAA, which to date still has not acknowledged an association between head impacts sustained by its athletes and problems later in life.
Thankfully, many of the misconceptions on concussions fortunately have been dispelled — including the idea that getting knocked out is something required to have a concussion or that having loss of consciousness means that the concussion is worse. We are increasingly realizing those ideas are not the case. The way to determine whether a concussion is severe or not is based on how long it takes for an individual to recover from a concussion.
G: What about head injuries in other sports? Are there any we would be surprised to hear put players at particularly high risk?
DD: One of the sports most associated with head impacts that people might not think about is cheerleading. Many of these athletes are involved in maneuvers that involve height and velocity. Any contact or collision sport puts individuals at risk of concussion. Sports like hockey, boxing and soccer are associated with many repetitive head impacts. Soccer athletes, in fact, are found to have higher rates of dementia later in life than one might expect from a sport that’s not considered to be a high-contact sport.
Because most of the focus when it comes to head injuries in sports has been on football — and, to a lesser extent, hockey — these other sports get less attention. I can’t speak to whether the organizations themselves have been proactive about ensuring the health and safety of their athletes, but I know that from a societal standpoint, female athlete [dominated] sports have gotten a lot less attention and focus than male dominated sports.