The level of unexplained eye pressure may help to understand the link between fitness and brain function

While exercise is known to strengthen mental function and improve mental health, the brain mechanisms of this connection are unknown. Now, researchers from Japan have found evidence of the missing link between aerobic fitness and brain function.

In a study published in Medicine & Science in Sport & Exercise, researchers from the University of Tsukuba have shown that the level of involuntary eye pressure (sEBR), which reflects the activity of the dopamine system, could be used to understand the link between brain activity and aerobic fitness.

The dopaminergic system is known to be involved in physical activity and exercise, and previous researchers have suggested that changes in mental activity may be mediated by activity in the dopaminergic system. However, a signal of activity in this system was needed to confirm this hypothesis, something the researchers at Tsukuba University were aiming to address.

“The dopaminergic system is associated with both active action and stimulating behavior, including physical activity,” says the study’s first author Ryuta Kuwamizu. “We used sEBR as a noninvasive measure of dopaminergic system function to test whether this is a possible link between aerobic fitness and brain function.”

To do this, the researchers asked healthy participants a dose of sEBR, a test of mental activity, and an anaerobic fitness test. They also measured brain activity during mental activity using near-infrared spectroscopy.

“As expected, we found an important correlation between aerobic fitness, mental activity, and sEBR,” explained Dr. Hideaki Soya, senior author. “Upon further study of these relationships, we found that the association between higher aerobic fitness and improved mental function was partially mediated by dopaminergic regulation.”

Moreover, activity in the left dorsolateral prefrontal cortex (l-DLPFC) during cognitive functioning was the same or lower in participants with higher sEBR compared to lower sEBR, even though those with higher sEBR and therefore higher neural efficiency had greater functional value.

Although previous studies have shown an association between aerobic fitness and brain function, it is the first to provide a neuromodulatory basis for this link in humans. Our data show that dopamine plays a vital role in linking fitness and aerobic experience. “

Ryuta Kuwamizu, First Author Study, University of Tsukuba

Given that neural efficiency in the l-DLPFC is a known feature of the dopaminergic system observed in individuals with higher fitness and functional activity, it is possible that neural efficiency in this region is somewhat centralized to ‘link between aerobic fitness and action activity.

In addition, physical inactivity may be associated with dopaminergic dysfunction. This information provides new directions for research into how fitness affects the brain, which may lead to better exercise routines. For example, exercise that specifically focuses on improving dopaminergic function can significantly increase motivation, mood, and mental function.