Researchers from Japan have found evidence of the missing link between aerobic fitness and cognitive function, according to a study published in Medicine & Science in Sports & Exercise. The findings revealed that spontaneous eye blink (sEBR), which reflects activity of the dopamine system, could be used to understand the connection between cognitive function and aerobic fitness.

Previous research has found that exercise-induced changes in cognitive function might be mediated by activity in the dopaminergic system, which is known to be involved in physical activity and exercise, according to the current study. However, a marker of activity in this system was needed to test this hypothesis in a future study.

"The dopaminergic system is associated with both executive function and motivated behavior, including physical activity," said study author Ryuta Kuwamizu in a press release. "We used sEBR as a non-invasive measure of dopaminergic system function to test whether it could be the missing link between aerobic fitness and cognitive function."

The researchers asked healthy participants to undergo a measure of sEBR, a test of cognitive function, and an aerobic fitness test. They additionally measured brain activity during the cognitive task using functional near-infrared spectroscopy.

"As expected, we found significant correlations between aerobic fitness, cognitive function, and sEBR," said senior author Hideaki Soya in a press release. "When we examined these relationships further, we found that the connection between higher aerobic fitness and enhanced cognitive function was mediated in part by dopaminergic regulation."

The results highlighted that activity in the left dorsolateral prefrontal cortex (I-DLPFC) during the cognitive task was the same or lower in participants with higher sEBR compared with lower sEBR, even though those with higher sEBR appeared to have greater executive function, according to study authors.

"Although previous studies have indicated that aerobic fitness and cognitive function are correlated, this is the first to provide a neuromodulatory basis for this connection in humans,” Kuwamizu said in the release. “Our data indicate that dopamine has an essential role in linking aerobic fitness and cognition.”

Neural efficiency in the I-DLPFC is a known characteristic of the dopaminergic system that has been observed in individuals with higher fitness and executive function. With this, it is possible that neural efficiency in this region partially mediates the association between aerobic fitness and executive function.

Physical inactivity may be related to dopaminergic dysfunction, which provides the study authors with new directions for research regarding how fitness affects the brain and may lead to improved exercise regimens. An example of this would be exercise that specifically focuses on improving dopaminergic function may particularly boost motivation, mood, and mental function.

Blink! The link between aerobic fitness and cognition. University of Tsukuba. Published February 1, 2021. Accessed February 3, 2021.