- A study suggests that 20 minutes of moderate cycling increases brain activity in the hippocampus, a region critical for learning and memory.
- This increased hippocampal activity may support memory consolidation, potentially helping the brain process and store information.
- Higher exercise intensity was associated with stronger brain activity, suggesting that exercise levels may influence the magnitude of the brain’s memory-related response.
Many different strategies and techniques exist to help maintain or improve a person’s memory. Often, many of these methods emphasize keeping the brain active.
These brain-training activities often focus on stimulating specific regions of the brain involved in memory, such as the hippocampus. In particular, the hippocampus plays an important role in memory consolidation, the process by which newly formed memories are strengthened into long-term memories.
Previously, neuroscientists have documented “ripples” of brain activity relevant to memory in mice and rats. However, they had been unable to confirm this link in humans.
Now, a new study, published in Brain Communications, suggests that brief sessions of physical exercise could alter human brain activity, triggering waves of ‘ripples’ that may support the brain to process and store information more effectively.
These findings provide some of the first direct evidence explaining how exercise benefits cognition in humans at the neural level.
Researchers have long known that physical activity is associated with improvements in memory and other cognitive functions. However, due to difficulties recording human brain activity, much of the previous evidence comes from behavioral studies or indirect imaging methods.
However, in this study, researchers directly recorded brain activity using intracranial electroencephalography (iEEG). Typically used for monitoring severe epilepsy, this technique involves implanting electrodes in the brain to observe neural signals with high precision.
Co-lead author Juan Ramirez-Villegas, PhD, a tenure-track research scientist at the Neuroscience Institute Alicante of the Spanish Research Council and the Miguel Hernández University of Elche spoke to Medical News Today about the advantages of this technique.
“These electrodes can record electrical signals produced by groups of neurons which are active together. This allows us to detect brief events of coordinated neural activity such as ripples, which are thought to play an important role in memory,” said Ramirez-Villegas.
“Because these recordings capture the brain’s electrical activity directly, they provide a level of detail that brain scans cannot. They allow us to observe the rapid dynamics of neural circuits in real time, giving us a much clearer window into how the brain processes information,” he added.
The team studied 14 participants aged 17 to 50 years who had electrodes implanted as part of epilepsy treatment. The 14 individuals completed a 20-minute session on a stationary bike, cycling at a comfortable pace.
The researchers chose this protocol as it was short and feasible to implement in a clinical setting. The team then measured brain activity both before and after the exercise session.
After exercising, the research team observed a significant increase in high-frequency ripple activity originating in the hippocampus. These ripples then spread toward other brain regions involved in processing and recalling information.
“Ripples are very brief bursts of highly synchronized electrical activity in the brain’s memory center, the hippocampus,” Ramirez-Villegas explained to us.
“In animals, they are known to play a key role in stabilizing memories after an experience. You can think of them as moments when the brain rapidly ‘reviews’ information, helping convert recent experiences into lasting memories,” he illustrated.
Ripple events describe brief bursts of synchronized neural activity. The researchers suggest these ripples are comparable to high-speed data transfers.
Experts believe these ripples help the brain consolidate and retrieve memories. Scientists previously observed these signals in rodents.
However, until now, evidence for ripple activity in humans had been limited.
The new recordings show that physical activity increases both the frequency of ripples in the hippocampus and their synchronization with other brain networks, suggesting stronger communication between regions involved in memory processing.
“The most surprising finding was not only that we observed measurable changes in hippocampal ripple activity. But also that exercise influences cortical structures just as well,” Ramirez-Villegas said.
“What is more, it is surprising how after a session of acute exercise, hippocampal-cortical communication seems to be enhanced, a phenomenon thought to be strongly linked to memory processing. This suggests that even a brief bout of physical activity can influence the neural dynamics involved in learning and memory,” he noteed.
Additionally, the study also found that higher heart rates during exercise were linked to stronger ripple activity afterward. This indicates that exercise intensity may influence the magnitude of the neural response.
“We found that participants who reached higher heart rates during exercise tended to show stronger ripple activity afterward. This suggests that the intensity of physical activity may influence how strongly the brain’s memory circuits respond.”
– Juan Ramirez-Villegas, PhD
The findings suggest that even a short workout could temporarily enhance the brain’s ability to encode or recall information.
The researchers propose that the surge in ripple activity may represent a neural mechanism underlying the well-known cognitive benefits of exercise.
Ramirez-Villegas noted what this tells us about how the brain processes memories: “Ripple activity in the hippocampus is considered a marker of memory-related neural processing. When ripple activity increases, the hippocampus may be more actively exchanging information with other brain regions.”
“Our findings raise the possibility that exercise enhances the neural processes that help stabilize or organize memories,” he said.
Previous research has shown that regular physical activity can improve memory across different age groups and may help
“Physical activity is already known to support brain health across the lifespan. Our findings suggest a potential neurophysiological mechanism through which exercise might benefit memory-related circuits,” Ramirez-Villegas added.
“Understanding these mechanisms could eventually help guide strategies aimed at preserving cognitive function,” noted the researcher.
While the results are promising, the research team cautions that the study involved a small group of participants with epilepsy. As such, the findings may not fully represent the general population.
However, the patterns observed were consistent with those from studies using functional MRI in healthy adults, suggesting that the effects likely extend beyond this group.
Ramirez-Villegas told MNT that an important next step will be to directly link these neural changes to memory retention:
“Future studies will combine neural recordings with behavioral tests to see whether changes in ripple activity translate into measurable improvements in learning or recall. This will help clarify how exercise influences the brain’s memory systems.”
Although more research is still necessary, these findings support growing evidence that even brief bouts of physical activity may help prepare the brain for learning and cognitive performance.
