When he first saw the data, Patrick Bellgowan figured he’d made a mistake. How else to explain it? A researcher at the University of Tulsa’s Laureate Institute for Brain Research, Bellgowan had been scanning the brains of college football players, comparing the results to scans of nonplayers. His focus was on the hippocampus, a seahorse-shaped area deep inside the brain that plays a huge role in emotional control and memory formation. Bellgowan knew that the hippocampus was very sensitive to traumatic brain injury. That contraction of the region was a hallmark of Alzheimer’s disease. That a comparable reduction in the volume also corresponded with chronic traumatic encephalopathy, a neurodegenerative disease linked to football, boxing along with other contact sports.
Hippocampus is 14% smaller
Still, he expected to see little difference in hippocampal size between a group of 50 college players and 25 nonplayers, mostly because everybody in the study was relatively healthful and young. And after that Rashmi Singh, a fellow researcher at the Laureate Institute brought a set of initial results to Bellgowan’s office. Are you sure? he said. That cannot be right. The numbers were stark. A group of 25 players with no history of reported commotion had hippocampus which was, on average, 14 percent smaller compared to those of a control group of 25 males of comparable age and health who did not play contact sports.
The potential risk of developing severe neurodegenerative diseases
Furthermore, the same brain region in the second group of 25 players who’d suffered a minimum of one clinically diagnosed concussion was, on average, 25 percent smaller compared to the control group, a larger difference in volume, Bellgowan says, than the variations scientists have observed between the brains of healthful people and patients suffering from Alzheimer’s disease or major depressive disorder. I cannot tell you how often times we checked this over, Bellgowan says. The effect size was really large. While much of the safety and health debate over football along with other contact sports focuses on the potential risk of developing severe, headline-grabbing neurodegenerative diseases like amyotrophic lateral sclerosis and CTE, a growing body of evidence suggests that both concussions and sub-concussive strokes can alter mood, cognition, and behavior while causing harm and structural changes to the brain.
Contact sports can be worse for your cognitive health
Put simply, contact sports can be worse for your cognitive health than previously assumed, even when you do not ultimately end up in a dementia ward. Consider: Bellgowan and his co-authors also found that the longer an athlete had played football, the smaller their left hippocampal region was. Football players also scored lower than nonplayers on tests of cognitive processing speed, and again, football career length had an inverse relationship with test results. An international research team detected the microstructural brain harm in concussed male and female college hockey players, the harm that cannot be seen with the standard.