Controlling the ball takes its toll: heading it in soccer alters brain function.

NEW YORK (HealthDay News)—Heading the ball can be a dramatic, game-changing move in a soccer match. But players pay a price every time they make this move, a new study says.

Bouncing a soccer ball on someone's head alters their brain, even if it doesn't result in a concussion, researchers reported in "Sports Medicine-Open."

MRIs of soccer players reveal that heading subtly alters brain chemistry and nerve function, causing slightly elevated levels of proteins associated with brain injuries.

“These findings suggest that even routine, asymptomatic nodding can produce subtle changes in the brain,” said lead researcher Danielle McCartney of the Lambert Initiative for Cannabinoid Therapeutics at the University of Sydney.

“The next step is to understand whether these changes accumulate over time, and what that might mean for players' long-term health,” he added.

“In the meantime, we join the calls for football players to be cautious and perhaps consider whether it is necessary to head the ball a lot, particularly in training.”

In the new study, researchers asked 15 players to head a ball 20 times in 20 minutes. The balls were launched at a constant speed from a machine, and each player also underwent a second stage of kicking the ball as a means of comparison.

MRIs revealed altered chemistry in a brain region involved in body movement, as well as decreased electrical conductivity in several areas.

This suggests that nodding affects how the brain uses energy and information is transmitted through white matter, the nerve tissue that connects different parts of the brain.

In turn, blood samples showed elevated levels of two proteins associated with brain injury and future risk of dementia: glial fibrillary acidic protein (GFAP) and neurofilament light (NFL).

The brain changes associated with heading the ball were much smaller than those found in people with dementia or concussion, and the researchers noted that none of the players showed any signs of cognitive decline after heading the ball.

“This study does not prove that heading causes dementia,” cautioned lead researcher Nathan Delang of the University of Queensland. “Our conclusion from the increased presence of these proteins, and from the study in general, is that heading the ball can cause subtle disruption in brain cells, even without obvious symptoms.”

“Elevated levels of these biomarkers indicate that brain cells have been altered at the microstructural level. The clinical and long-term significance of these small elevations is still being studied, particularly in relation to how much and what pattern of exposure might lead to effects on brain structure and function.”

Some countries, including the United States and the United Kingdom, are gradually introducing restrictions on heading, including banning the practice among young players.

At a glance

Risk of dementia

In the study of the effects of heading a soccer ball, blood samples showed elevated levels of two proteins associated with brain injury and future risk of dementia: glial fibrillary acidic protein (GFAP) and neurofilament light (NFL).

No signs

No player showed any signs of cognitive impairment after heading the ball.