Neuroscientists have captured direct evidence that a brief burst of aerobic exercise creates ‘brain ripples’ in the hippocampus, strengthening memory storage and retrieval.
Memory can be such a fickle thing. Whether trying to remember people’s names, recall a list of items you need from the shop, or preparing for an important exam or job interview, information that was in your head one minute can flutter out the next.
But there is an easy way you can give your memory an instant boost when trying to learn new information — jump on an exercise bike for a few minutes or take a brisk walk. Research shows that a brief bout of physical exercise can create “ripples” of activity in your brain that help you store and retrieve memories.
The Science of Brain Ripples
A new study led by neuroscientist Michelle Voss at the University of Iowa has peered inside the heads of participants immediately after exercise, observing tiny bursts of electrical activity flowing between brain cells that are known to be important for consolidating memories.
These “brain ripples” are a phenomenon where many neurons activate together, playing a key role in how the brain packages and stores memories during sleep and periods of quiet rest. The team monitored the brains of participants, all of whom had drug-resistant epilepsy but were studied in healthy brain regions, to see what would happen after a brief burst of activity.
They found that after exercise, there was an increase in ripples in the hippocampus, an area of the brain critically important for memory, as well as in other regions the hippocampus is connected to.
“These pulses were also more finely synchronised with neural activity in the rest of the brain,” Voss says.
This synchrony, she believes, may provide a biological explanation for why people often remember information better if they exercise shortly after learning it. And it only took a brief burst of activity to increase brain ripples — showing that even short bursts of activities could benefit our memory.
Why Aerobic Exercise, Not Stretching
It has long been known that exercise boosts cognition. Physical activity improves how well we perform on tasks and strengthens brain areas vulnerable to ageing, potentially slowing down cognitive decline.
But physical exercise can also strengthen the hippocampus, which is why it can have a positive effect on our memory. Moderate exercise a few times a week, for instance, has been found to increase the size of the hippocampus. Other studies have shown that the timing of the exercise can make a difference too, going for a walk four hours after learning can improve memory retention and subsequent retrieval compared to exercising immediately afterwards.
Critically, stretching exercises, by comparison, did not provide any memory boost. The active ingredient appears to be aerobic exercise, or cardio — activities that raise your heart rate and get you breathing harder.
Unique Window Into the Brain
Until now, it has been difficult for scientists to understand the processes at play. Voss’s team collaborated with neurosurgeons who monitor electrical activity in patients undergoing evaluation for epilepsy surgery. These patients temporarily had electrodes implanted in their brains, allowing the team to observe electrical activity before and after exercising on an exercise bike.
These ripples occur too quickly to be picked up by standard brain scans, making this study the first to show how exercise influences the brain’s electrical activity directly.
“That presents us with a unique opportunity to understand how the human brain works with direct measurements of electrical signalling, which is the primary currency of how the brain works,” Voss says.
The More You Exercise, The Greater the Benefit
Another recent study found that the more we exercise and the fitter we become, the more benefit our brain gets after a single workout. Any physical activity is clearly beneficial, but this new research revealed that the brain benefits increase the more active we are.
This happens because higher cardiovascular fitness and muscle mass enable the body to produce more of a protein vital for forming new brain connections, called Brain-Derived Neurotrophic Factor (BDNF).
“There’s a reason to stay active because you will benefit more every time,” says Flaminia Ronca, an exercise physiology researcher at University College London who led that study. “If you stick with exercise for six weeks, you will reap bigger benefits from any further sessions.”
Practical Takeaways for Better Memory
Research shows that a single workout can improve focus for up to two hours afterwards, as well as immediately boost levels of the “feel-good” hormone dopamine. To harness these memory-enhancing effects:
- Time it right: Exercise four hours after learning new information for optimal memory retention
- Keep it brief: Even short bursts of aerobic activity increase brain ripples
- Choose cardio: Brisk walking, cycling, jogging, or swimming — stretching alone won’t produce the same effect
- Stay consistent: The fitter you become, the greater the cognitive benefit from each workout
A New Way to Think About Ageing
Voss hopes the work helps reframe public health messaging around physical activity and could help us think about ageing better too, especially as strengthening the areas important for memory could help protect the brain from cognitive decline.
For anyone wanting to improve their memory, whether a student cramming for exams, a professional preparing a presentation, or an older adult concerned about cognitive health, the prescription is simple: get moving, and keep moving.