Study hypothesizes that weight cutting leads to increased brain volume reduction

Author Erik Magraken is a British Columbia litigation lawyer, combat sports law consultant, combat sports law blogger, and deeply, deeply appreciated UGer.

The Professional Fighters Brain Health Study has generated much useful data. The study, conducted out of the Cleveland Clinic Luo Ruvo Center for Brain Health in Las Vegas has been compiling data since 2011 giving insight into the tolls professional fighting takes on athletes’ brains.

The latest data, published in Neurotrauma Reports, canvasses brain volume reduction reviewing data from both professional boxers and mixed martial artists and comparing the data across lower, mid range, and heavier weight classes.

In the recent study, titled Effect of Weight Class on Regional Brain Volume, Cognition, and Other Neuropsychiatric Outcomes among Professional Fighters, the authors followed fifty-three boxers and 103 MMA fighter. The fighters underwent volumetric magnetic resonance imaging (MRI) and neuropsychological testing. When comparing the data, broken down into light weight, middleweight, and heavyweight fighters, the authors noted that while heavier fighters had greater annual reduction of regional brain volume, lower weight class fighters “suffered greater reductions in regional brain volume on a per-fight basis.“ 

The authors noted further research is needed on this finding but hypothesized in the following comments that the tolls of extreme weight cutting could be playing a role: 

In certain regions (left thalamus in boxers, right putamen in MMA fighters), lightweight fighters demonstrated greater yearly reductions in volume on a perfight basis. The widespread practice of rapid weight loss through dehydration and caloric restriction among professional fighters to meet weight class requirements may be more common in lighter-weight-class fighters and underlie their increased susceptibility to brain injury with increasing number of official fights. Although fighters may begin re-feeding and re-hydration immediately after weigh-in, previous studies have found dehydration to be highly prevalent among fighters at the time of competition. 

Dehydration secondary to rapid cutting of weight may worsen TBI-induced neurotrauma, potentially contributing to the observed association of lighter weightclass with worse outcomes on a per-fight basis. This effect would likely only persist during the acute period following dehydration, and as such would only alter the impact of TBIs sustained during professional bouts. It has been proposed that dehydration-induced changes in brain morphology may alter mechanical cushioning and strain mitigation provided in part by cerebrospinal fluid within the subarachnoid space and lateral ventricles. 

Although the exact mechanisms are unclear, the present findings are consistent with this hypothesis and highlight the need for future research into the influence of weight-cutting on the long-term brain health of professional fighters. It should also be considered that heavyweights may have more comorbidities (i.e. diabetes, metabolic syndrome, etc.) potentially exacerbating neurodegenerative processes through pro-inflammatory pathways. This might contribute to greater yearly decrements in heavyweights despite the greater volume of strikes absorbed by lightweights on a per-fight basis and the possible exacerbations from effects of weight-cutting. Future work is required to elucidate these complex relationships

The full abstract reads as follows:

Traumatic brain injury (TBI) is a common source of functional impairment among athletes, military personnel, and the general population. Professional fighters in both boxing and mixed martial arts (MMA) are at particular risk for repetitive TBI and may provide valuable insight into both the pathophysiology of TBI and its consequences. Currently, effects of fighter weight class on brain volumetrics (regional and total) and functional outcomes are unknown. Fifty-three boxers and 103 MMA fighters participating in the Professional Fighters Brain Health Study (PRBHS) underwent volumetric magnetic resonance imaging (MRI) and neuropsychological testing. Fighters were divided into lightweight (£139.9 lb), middleweight (140.0–178.5 lb), andheavyweight (>178.5 lb). Compared with lightweight fighters, heavyweights displayed greater yearly reductions in regional brain volume (boxers: bilateral thalami; MMA:leftthalamus, right putamen) and functional performance (boxers: processing speed, simple and choice reaction; MMA:TrailsA and B tests). Lightweights suffered greater reductions in regional brain volume on a per-fight basis(boxers: left thalamus;MMA:rightputamen).Heavyweight fightersbore greater yearly burden of regional brain volume and functional decrements, possibly related to differing fight dynamics and force of strikes in this division. Lightweights demonstrated greater volumetric decrements on a per-fight basis. Although more research is needed, greater per-fight decrements in lightweights may be related to practices of weightcutting, which may increase vulnerability to neurodegeneration post-TBI. Observed decrements associated with weight class may result in progressive impairments in fighter performance, suggesting interventions mitigating the burden of TBI in professional fighters may both improve brain health and increase professional longevity

Join the discussion on this topic...

Share