Sports players with at least ten years’ experience of contact sport are experiencing an array of health consequences as a result of repetitive head impacts, a new study has found.
While they may appear healthy, research has established that athletes have problems with inflammation, energy production and coordination.
These are as a direct result of the head impacts they experience, Northwestern Medicine and Pennsylvania State University report.
The head impacts individually may not have been severe enough to cause a clinical concussion, but show the cumulative effect of repeated blows to the head over several seasons.
The issues were found in measures that show abnormal regulation of inflammation, less coordinated movement and abnormalities in how cells produce energy, and add further to existing research showing the long-term impact of head injury in sport.
These three measures are significantly related to each other before the football season and to changes observed across the football season. They were also related to the number of head impacts a player received over the season.
“These findings support over a decade of reports about the negative effects of repetitive head impacts, along with studies of animal brain injury,” said co-senior author Dr Hans Breiter, professor of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine.
“At this point, it appears the canary is dead in the coal mine.”
“This problem affects much of youth and professional impact sports in the US, along with training of US military personnel,” said co-senior author Dr Semyon Slobounov, professor of neurosurgery at Penn State College of Medicine.
This study – which assessed college American Football players – used measures previously found to be increased in football players before the season began and at a level similar to what is observed in individuals needing hospital treatment for a concussion.
These measures have been associated with inflammation regulation and were increased over the course of the football season. In this study, these regulatory measures of inflammation were linked with measures of energy production and coordination.
The football players’ coordination – measured as accuracy maintaining balance, speed at correcting balance and ability to remember movements – related to measures indicative of energy production issues and inflammation regulation.
Before and during the season, the higher the regulatory measures of inflammation were, the lower the coordination measures.
The study of repetitive head impacts in sport also showed abnormalities in energy production, resulting in decreased energy. These abnormalities linked abnormal inflammation regulation with reduced coordination. They also showed relationships with measured head impacts.
“A lack of energy can have significant consequences, especially in regard to brain function, raising questions of the long-term consequences,” said co-lead author Sumra Bari, a postdoctoral fellow at the department of psychiatry and behavioral sciences at Northwestern.
To perform this study, 23 athletes from a collegiate football team were enrolled who had been playing football for an average of 11 years. The athletes participated in a full season of competitive collegiate play.
Nine of them had experienced one to two concussions in prior seasons. Blood was collected and coordination was tested both before and after the football season.
The coordination tests were designed to assess balance and to test their ability to remember a virtual pathway – collectively referred to as “coordination.”
In addition, head impacts were recorded at all practices across the season using sensors which were attached to the players’ helmets.
Future research should expand to a larger cohort of athletes to confirm the findings, scientists said.
“Ultimately, the goal is to develop preventative interventions that minimise abnormal changes in the brain that have been observed in studies of contact sport athletes time and time again,” said lead author Nicole Vike, a postdoctoral fellow at the department of psychiatry and behavioral sciences at Northwestern.
“Collectively, we need to use interdisciplinary approaches, like those used here, to better quantify the unseen damage of contact sports.”
