LAS VEGAS — Combat sports like boxing and mixed martial arts (MMA) can be a thrill to watch, but the combatants put themselves at risk of far more than just a black eye or bruised rib. Studies show that repeated hits to the head are absolutely detrimental to long-term brain health and cognition. However, new research indicates that there is hope for a fighter’s brain in retirement.
Study authors report boxers and MMA fighters may experience some recovery in their thinking and memory skills, as well as brain structure, after leaving the ring.
“Repetitive hits to the head increase the risk of long-term neurologic conditions like chronic traumatic encephalopathy (CTE), cognitive and behavior problems and parkinsonism,” says study author Aaron Ritter, MD, of Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas, in a media release. “However, we haven’t known what happens to people who have been fighting and then stop fighting. The good news is we saw some improvement in thinking and memory scores in these retired fighters.”
Memory and thinking speed improves after hanging up the boxing gloves
Researchers studied 45 retired, male fighters who hadn’t competed in two years and had an average age of 32. This group consisted of 22 boxers, 22 MMA fighters, and one martial artist. Next, the team gathered a group of 45 active male fighters, consisting of 17 boxers, 27 mixed martial artists, and one martial artist, with an average age of 30. The study authors then matched both groups according to age, education, race, and number of fights at the start of the study.
All of the fighters had a professional fight within a year of the start of the study. Then, over the following two years, retired fighters stopped fighting while active fighters kept participating in professional bouts. Over a three-year period, all fighters underwent various brain scans and completed a series of tests gauging how well their brains were functioning at the beginning and end of the study.
Additionally, researchers considered each fighter’s fight history. Half of the participants also underwent blood tests for a biological marker of brain injury known as neurofilament light chain, which is a nerve fiber component that is detectable in the blood when the fibers are damaged. Participants also took tests measuring verbal memory, executive functioning, motor speed, and processing speed.
Retired fighters showed improvements in their verbal memory, motor speed, and processing speed scores over time, while active fighters’ scores in the same categories either remained stagnant or showed subtle declines. Researchers used an FDA-approved thinking and behavior test to measure verbal memory. Over time, retired fighters showed an average increase of three points, while active fighters had an average decrease of two points.
What’s going on in a fighter’s brain?
Different patterns of change over time appeared between retired and active fighters regarding the ability to detect and respond to rapid changes in the environment, as well as how long it takes to complete tasks. Retired fighters also displayed a drop in their neurofilament light chain levels from the start to the end of the study, while active fighters saw those same levels remain steady.
The team measured brain thickness in the areas of each fighters’ brains which control emotion, memory, and executive function — which is a person’s ability to plan, focus, and manage multiple tasks. Among 68 total brain regions measured, 54 showed a consistently changing trajectory. Thickness measures stabilized for retired fighters while subtly declining over time for active fighters.
“The results of this study suggest a recovery of cognitive functioning in fighters who are no longer exposed to repetitive hits to the head,” Dr. Ritter concludes. “Future research is needed to determine if there is a time in a fighter’s career where recovery is less likely to happen or to identify factors that might indicate greater risk for developing a neurodegenerative condition.”
It’s worth noting researchers were unable to determine how many repetitive hits to the head each fighter sustained during their career. For instance, plenty of head impacts happen during training, which means they go largely unnoticed.
The study is published in the journal Neurology.