New Study Shows Brain’s Arousal System Plays a Role in Cognitive Benefits of Exercise
A groundbreaking new study published in NeuroImage has shed light on the neural mechanisms behind the cognitive benefits of exercise. Researchers at the University of Tsukuba have found evidence that the brain’s arousal system, particularly the catecholaminergic system originating from the locus coeruleus (LC), is involved in the positive effects of exercise on executive function.
Previous research had already established that very light-intensity exercise, such as yoga or slow running, could enhance cognitive performance without causing stress or negative mood responses. However, the underlying neural mechanisms for this improvement were still unclear. The researchers sought to better understand how the brain’s arousal system contributes to these benefits.
According to study author Hideaki Soya, a professor at the University of Tsukuba, the COVID-19 pandemic has led to a decline in physical activity, which can have severe cognitive and mental health consequences. As a potential countermeasure, stress-free mild exercise, such as yoga, tai-chi, and slow mindful running, could be a powerful treatment for brain health. Previous translational studies on animals and humans have demonstrated that exercise stimulates brain function even at very light intensity.
To investigate further, the researchers focused on the pupil as a window into the mind. They designed an experiment involving 34 healthy young adults, with 6 female and 28 male participants. Individuals with no history of neurological or psychiatric disorders were selected to ensure the study’s results were not confounded by other conditions.
The experiment followed a crossover design, where participants went through two conditions on separate days: a resting control condition and a very-light-intensity exercise condition. In the exercise condition, participants engaged in 10 minutes of very light-intensity cycling, tailored to their aerobic capacity. In the control condition, they rested.
During the experiment, the researchers collected data using an eye-tracking device to measure changes in the participants’ pupil diameter. They also used functional near-infrared spectroscopy (fNIRS) to monitor prefrontal cortex activity during an executive function task called the color-word Stroop task, which requires cognitive control to overcome interference.
The results revealed that pupils dilated during very light exercise, and the extent of this dilation was associated with subsequent improvements in executive function performance. Furthermore, the fNIRS measurements showed increased activity in the left dorsolateral prefrontal cortex, a region of the brain associated with cognitive control and decision-making.
“These findings suggest that even 10 minutes of very light exercise can enhance the function of the prefrontal cortex,” said Soya. “This is good news for those who dislike exercise.”
The study also highlights the potential of pupil observation as a novel biomarker for predicting the effects of exercise on the brain. However, Soya emphasized the need for caution when applying these results practically, as the experiments were strictly controlled for light and visual stimuli.
Moving forward, the researchers hope to delve deeper into the neuroscientific mechanisms underlying the impacts of exercise on the brain, particularly mild exercise. They encourage individuals to explore other studies and consider incorporating very light exercise into their daily routines.
The study, authored by Ryuta Kuwamizu, Yudai Yamazaki, Naoki Aoike, Taichi Hiraga, Toshiaki Hata, Michael A. Yassa, and Hideaki Soya, provides valuable insights into the cognitive benefits of exercise and offers new avenues for understanding the effects of physical activity on the brain.